Schedule II (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
SEC Schedule, 12-09, Valuation Allowances and Reserves, Amount	$ 74	$ 68	$ 98	$ 119
Net (credits) charges to expenses	23	19	14
SEC Schedule, 12-09, Valuation Allowances and Reserves, Deduction	(17)	(19)	(18)
SEC Schedule, 12-09, Valuation Allowances and Reserves, Increase (Decrease) Adjustment	$ 0	$ (30)	$ (17)