Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Income Tax Contingency [Line Items]
Income tax expense (benefit)	$ 1	$ 9
Minimum
Income Tax Contingency [Line Items]
Reasonable possible decrease in unrecognized tax benefits	30
Maximum
Income Tax Contingency [Line Items]
Reasonable possible decrease in unrecognized tax benefits	37
Out of period adjustments - stock compensation permanent differences [Member]
Income Tax Contingency [Line Items]
Income tax expense (benefit)	2
Out of period adjustments - write-off of income tax payables [Member]
Income Tax Contingency [Line Items]
Income tax expense (benefit)	$ 3