Leases - Lease Cost and Other Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Lease, Cost [Abstract]
Finance lease cost	$ 4	$ 3	$ 0
Operating lease cost	91	100	109
Short-term lease cost	3	3	3
Variable lease cost	9	6	6
Sublease income	(2)	(17)	(17)
Total lease cost	105	95	101
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from operating leases	102	101	104
Financing cash flows from finance leases	6	1	0
Right-of-use assets obtained in exchange for new finance lease liabilities	16	5	0
Right-of-use assets obtained in exchange for new operating lease liabilities	$ 47	$ 4	$ 215
Finance leases:
Weighted average remaining lease term (in years)	3 years 7 months 6 days	1 year 1 month 6 days
Weighted average discount rate	2.46%	4.79%
Operating Leases [Abstract]
Weighted average remaining lease term (in years)	4 years 8 months 12 days	5 years 3 months 18 days
Weighted average discount rate	5.44%	5.63%