Commitments and Contingencies - Additional Information (Details) - USD ($)	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020	Jun. 30, 2017
Debt Instrument [Line Items]
Letters of credit	$ 18,000,000
Operating lease costs	22,000,000	$ 19,000,000
Operating lease liabilities, payments	18,000,000
Right-of-use assets obtained in exchange for operating lease liabilities	$ 21,000,000
Weighted-average lease remaining lease term	8 years
Weighted-average discount rate	3.40%
Undiscounted cash flows	$ 340,000,000
Unrecognized tax benefits	23,000,000
2022 Notes
Debt Instrument [Line Items]
Principal	135,000,000		$ 169,000,000	$ 782,500,000
2030 Notes
Debt Instrument [Line Items]
Principal	$ 1,500,000,000		$ 1,500,000,000
Minimum
Debt Instrument [Line Items]
Operating lease term	4 years
Maximum
Debt Instrument [Line Items]
Operating lease term	14 years