Waymo, the self-driving car company owned by Google's parent Alphabet, closed a $5 billion term loan on Thursday. It is the first time Waymo has borrowed money instead of selling shares, and the company called it "an important step in our evolution into a scaling commercial enterprise."

PIMCO, Blackstone and Sixth Street led the group of lenders. Capital Group, Loomis Sayles and T. Rowe Price also lent large sums, and Goldman Sachs ran the deal, Waymo said. The money will help the company grow its ride-hailing service across the United States and in other countries.

The loan grew as talks went on. Waymo began negotiating in early September with a target of more than $3 billion, Quartz reported. Lenders were set to earn more than five percentage points above the benchmark rate, and the debt is expected to carry no credit rating.

Until now, Waymo has relied on money from Alphabet and outside investors. In February it raised $16 billion in a share sale that valued the company at $126 billion, TechCrunch reported. Waymo now runs paid robotaxi service in 15 U.S. markets and is testing in London and Tokyo.

Detroit is one of the next stops. On Tuesday, Waymo began fully driverless testing in the city, with no safety driver behind the wheel, the Detroit Free Press reported. For now, only Waymo employees can ride. The cars are driving downtown and in nearby neighborhoods such as Corktown, Midtown, Hamtramck and Indian Village.

"We'll follow our safety framework and serve riders in Detroit when we've properly validated our technology in the city and our local operations are ready," spokesman Chris Bonelli said. Waymo gave no date for public rides. Detroit residents can download the Waymo app ahead of a launch.

Growth has also drawn scrutiny. Federal safety regulators are investigating Waymo cars that illegally passed stopped school buses, TechCrunch reported.

What we know: Waymo closed a $5 billion loan and started driverless tests in Detroit.
What we don't: When Detroit riders can book a driverless trip.