Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Operating Loss Carryforwards [Line Items]
Effective tax rate on income from continuing operations (as a percent)	(2.40%)	16.10%	18.00%	16.00%
Valuation allowance	$ 17		$ 17		$ 19
Gross unrecognized tax benefits	102		102		100
Unrecognized tax benefits net of federal tax benefits that would affect the effective tax rate	73		73		67
Increase (decrease) in interest and penalties	1	$ 1	1	$ 2
Payable related to accrued interest and penalties	9		9		$ 8
Minimum [Member]
Operating Loss Carryforwards [Line Items]
Decrease in gross unrecognized tax benefits due to resolution of audits and statute expirations	0		0
Maximum [Member]
Operating Loss Carryforwards [Line Items]
Decrease in gross unrecognized tax benefits due to resolution of audits and statute expirations	10		10
State and Local [Member]
Operating Loss Carryforwards [Line Items]
State net operating losses	$ 20		$ 20