Income Taxes (Unrecognized Tax Benefits) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	$ 13
Increase in Unrecognized Tax Benefits is Reasonably Possible	5
Unrecognized Tax Benefit Rollforward [Abstract]
Unrecognized Tax Benefits, Beginning Balance	263	$ 126	$ 66
Additions for tax positions of prior years	13	152	83
Reductions for tax positions of prior years	(152)	(15)	(3)
Settlements	(111)	0	(20)
Unrecognized Tax Benefits, Ending Balance	$ 13	$ 263	$ 126