Mike Segar/Reuters Customers in a Verizon Wireless store in Manhattan.

Updated, 9:15 p.m. |

Verizon Communications agreed on Monday to spend $130 billion to take full control of its enormous wireless unit because it said it believed that the American desire for cellphones and broadband services was not yet nearly sated.

In buying out its longtime partner, Vodafone of Britain, the telecommunications giant is also striking a takeover more than a decade in the making, taking advantage of receptive debt markets and its own strong stock.

And Vodafone will be flush with cash to reinvest in its own businesses and to buy competitors in Europe and emerging markets.

The roughly 100 million Verizon Wireless customers probably will not see any change in their services, at least at first. But the telecommunications industry is very much in flux as new competitors like SoftBank of Japan have entered the market, while new opportunities for wireless services have emerged. Verizon viewed gaining full control of its biggest business as essential to addressing those trends. In the most recent quarter, wireless services accounted for $20 billion of the company’s nearly $30 billion in revenue.

Among its plans is bundling mobile broadband services with wired offerings like high-speed, fiber-optic connections.

“There’s a big phase of growth in the U.S. telecom market,” Lowell C. McAdam, Verizon’s chief executive, said in an interview. “The timing was perfect for us.”

The deal is enormous by any measure, with the price nearly equaling Verizon’s entire market value. As part of the complex deal, Verizon agreed to pay $58.9 billion in cash and an additional $60.2 billion worth of its shares to Vodafone, the latter of which will be distributed to Vodafone’s shareholders. Verizon will also sell its minority stake in Vodafone’s Italian business for $3.5 billion, as part of a series of smaller transactions tied to the deal. The amount it is paying is merely for 45 percent of Verizon Wireless, implying that the wireless unit is being valued at nearly $290 billion.

Vittorio Colao, chief executive of Vodafone, told reporters on Monday that the deal offered good value for his shareholders. “It was a good move for both partners, and we were able to find the right price,” he said.

The deal comes at a critical time for the American telecommunications industry. The country’s wireless business has had a gradual slowdown in subscriber growth in the last few years because many people who want a cellphone already have one. In the second quarter, the growth rate of the American wireless market was 2.2 percent — the first time it has fallen below 2.5 percent, said Craig Moffett, an analyst for Moffett Research.

The carriers, including Verizon, have said newer devices like tablets would help improve growth. But Mr. Moffett said that about 90 percent of the tablets that people were buying connect only to Wi-Fi networks, not cellular service. For wireless carriers, other markets for potential growth include cars or home security systems. But it is unclear whether those revenue streams will provide much growth to the industry.

“All those futuristic visions are almost certainly real,” Mr. Moffett said. “The question is whether they are big enough to really move the needle for an industry the size of the U.S. wireless market.”

Mr. McAdam pointed to the emergence of new, data-hungry uses across sectors as disparate as health care and education. “I don’t think the wireless market is losing steam at all,” he said.

For Vodafone, the deal will provide a huge war chest that could help it reshape the European telecommunications industry. The industry has suffered lackluster earnings and growing international competition, leading regulators to push for carriers to invest in new high-speed data networks that would stand toe-to-toe with those in the United States and South Korea.

Vodafone has committed to spending about $10 billion over three years in high-speed cellphone and broadband services across its markets in Europe and the developing world.

It would use another $20 billion from the sale of its Verizon Wireless stake to reduce its debt burden, but Mr. Colao said the company could still look to complete further acquisitions if it found the right targets.

“If we find good opportunities, we would look at those assets,” he said.

Born 14 years ago when Vodafone agreed to merge its United States operations with Bell Atlantic, Verizon Wireless became the largest cellphone operator in the United States, keeping pace with AT&T.

Executives on both sides have long discussed how to end the joint venture. Several options were floated over the years, according to Mr. McAdam, including merging Verizon’s and Vodafone’s entire companies.

But Vodafone often hesitated about ending a highly lucrative partnership, one that paid it a multibillion-dollar dividend every year. The onset of the European financial crisis further solidified the British company’s desire to keep a steady and stable source of income.

Still, progress appeared to emerge in the last three years. Mr. McAdam became Verizon’s chief executive in 2010, forming what people briefed on the matter described as a solid relationship with Mr. Colao, his counterpart at Vodafone.

About a year ago, Mr. McAdam said, he began seriously examining buying full control of Verizon Wireless, speaking with Mr. Colao and Vodafone’s chairman, Gerard Kleisterlee. Both sides agreed that the status quo was not an option.

Verizon turned to a cadre of advisers, including Guggenheim Partners; Paul J. Taubman, a former Morgan Stanley rainmaker; JPMorgan Chase ; Morgan Stanley; Bank of America Merrill Lynch ; and Barclays . Vodafone relied upon UBS and Goldman Sachs .

Known as “Project River,” with Verizon called “Hudson” and Vodafone “Thames,” the talks continued in fits and starts. Rumors of potential takeover structures — in one, Verizon and AT&T would team up to buy Vodafone, an idea never seriously considered — began to spread throughout the markets, prompting each side to clamp down on leaks.

But even during quiet periods this year, the Verizon team consulted regularly with the likes of Jamie Dimon of JPMorgan, James P. Gorman of Morgan Stanley and Alan D. Schwartz of Guggenheim, Mr. McAdam said.

One important issue was making sure Verizon could afford the deal. The company’s bankers insisted that the debt markets could support the sheer amount of bonds expected to be issued. Verizon’s underwriters are expected to sell more than $40 billion worth of paper, making the company the biggest issuer of bonds around.

The telecommunications company and its bankers also held lengthy consultations with debt ratings agencies, eager to preserve Verizon’s investment-grade credit rating.

The pieces finally fell into place in mid-July. Mr. McAdam, who was in San Francisco to open a Verizon innovation center, agreed to meet at a hotel with Mr. Colao, who was flying back from Australia.

“Things locked up in place like a Rubik’s Cube,” Mr. McAdam said.

Brian X. Chen contributed reporting.

Justin Sullivan/Getty Images Lowell McAdam, Verizon’s chief executive, has said his company can afford a big deal.