Revenue Recognition - Narrative (Details) - USD ($) $ in Millions |
9 Months Ended | |
|---|---|---|
Sep. 30, 2021 |
Sep. 30, 2020 |
|
| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] | ||
| Increase in contract assets | $ 78 | |
| Increase in contract liabilities | 218 | |
| Revenue recognized | 1,900 | $ 1,500 |
| Revenue, remaining performance obligation | $ 17,300 | |
| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-10-01 | ||
| Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items] | ||
| Remaining performance obligation, percentage | 88.00% | |
| Remaining performance obligation, expected timing of satisfaction period | 24 months | |