Leases (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Leases [Abstract]
Operating leases	$ 22	$ 24	$ 45	$ 48
Short-term leases	1	1	1	1
Lease expense	23	25	46	49
Less: sublease income	0	0	0	0
Net lease cost	23	25	46	49
Cash payments to settle a lease liability reported in cash flows	27	28	53	55
Right-of-use assets obtained in exchange for new lease liabilities	$ 7	$ 4	$ 19	$ 18
Weighted average discount rate (percent)	2.41%	2.94%	2.41%	2.94%
Weighted average remaining lease term (in years)	4 years 9 months 18 days	4 years 10 months 24 days	4 years 9 months 18 days	4 years 10 months 24 days