Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Operating Loss Carryforwards [Line Items]
Effective tax rate on income from continuing operations (as a percent)	13.40%	15.90%
Benefit related to utilization of NOL due to the CARES Act	$ 144
Valuation allowance	16		$ 19
Gross unrecognized tax benefits	98		100
Unrecognized tax benefits net of federal tax benefits that would affect the effective tax rate	68		67
Increase (decrease) in interest and penalties	1	$ 1
Payable related to accrued interest and penalties	9		$ 8
Minimum [Member]
Operating Loss Carryforwards [Line Items]
Decrease in gross unrecognized tax benefits due to resolution of audits and statute expirations	0
Maximum [Member]
Operating Loss Carryforwards [Line Items]
Decrease in gross unrecognized tax benefits due to resolution of audits and statute expirations	10
State and Local [Member]
Operating Loss Carryforwards [Line Items]
State net operating losses	$ 31