Debt - 2019 Cash Convertible Senior Notes (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions |
12 Months Ended | |||
|---|---|---|---|---|
Dec. 02, 2019 |
Dec. 31, 2020 |
Dec. 31, 2019 |
Dec. 31, 2018 |
|
| Debt Instrument [Line Items] | ||||
| Repayments of Convertible Debt | $ 0 | $ 1,150 | $ 0 | |
| Two Thousand Nineteen Cash Convertible Senior Notes [Member] | ||||
| Debt Instrument [Line Items] | ||||
| Repayments of Convertible Debt | $ 1,150 | |||
| Private Placement | ||||
| Debt Instrument [Line Items] | ||||
| Class of Warrant or Right, Number of Securities Called by Warrants or Rights | 11,180 | |||
| Exercise price of warrants (in dollars per share) | $ 133.32 | |||