Leases - Schedules of Components of Lease Expense, Supplemental Cash and Noncash And Balance Sheet Information (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Lease expense
Operating lease expense	$ 42	$ 42	$ 129	$ 122
Sublease income	(2)	(2)	(6)	(4)
Lease expense, net	40	40	123	118
Cash paid for amounts included in the measurement of lease liabilities
Operating cash flows from operating leases	42	40	126	113
Right-of-use (“ROU”) assets obtained in exchange for operating lease liabilities	$ 47	$ 15	$ 58	$ 261
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Other assets		Other assets		Other assets
Operating lease ROU assets	$ 645		$ 645		$ 707
Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Accrued expenses and other current liabilities		Accrued expenses and other current liabilities		Accrued expenses and other current liabilities
Other current operating lease liabilities	$ 135		$ 135		$ 144
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Deferred tax liability and other long-term liabilities		Deferred tax liability and other long-term liabilities		Deferred tax liability and other long-term liabilities
Operating lease liabilities	$ 616		$ 616		$ 642
Total operating lease liabilities	$ 751		$ 751		$ 786
Weighted-average remaining lease term—operating leases	6 years 3 months 18 days		6 years 3 months 18 days		6 years 10 months 24 days
Weighted-average discount rate—operating leases	3.00%		3.00%		3.00%