Revenue from Contracts with Customers - Contract Costs (Details) - USD ($) |
3 Months Ended | 6 Months Ended | |||
|---|---|---|---|---|---|
Jun. 30, 2021 |
Jun. 30, 2020 |
Jun. 30, 2021 |
Jun. 30, 2020 |
Dec. 31, 2020 |
|
| Capitalized Contract Cost [Abstract] | |||||
| Deferred incremental costs to obtain contracts | $ 1,200,000,000 | $ 1,200,000,000 | $ 1,100,000,000 | ||
| Average amortization period, deferred contract costs (in months) | 24 months | 24 months | |||
| Amortization of deferred costs | $ 264,000,000 | $ 205,000,000 | $ 512,000,000 | $ 410,000,000 | |
| Impairment losses recognized on deferred contract cost assets | $ 0 | $ 0 | $ 0 | $ 0 | |