Leases (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Leases [Abstract]
Operating leases	$ 22	$ 23	$ 67	$ 71
Short-term leases	0	1	1	2
Lease expense	22	24	68	73
Less: sublease income	0	0	0	0
Net lease cost	22	24	68	73
Cash payments to settle a lease liability reported in cash flows	25	27	78	82
Right-of-use assets obtained in exchange for new lease liabilities	$ 2	$ 8	$ 21	$ 26
Weighted average discount rate (percent)	2.37%	2.86%	2.37%	2.86%
Weighted average remaining lease term (in years)	4 years 7 months 6 days	4 years 10 months 24 days	4 years 7 months 6 days	4 years 10 months 24 days