Income Taxes (Unrecognized Tax Benefits) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Document Period End Date	Dec. 31, 2019
Beginning balance	$ 107	$ 56
Additions related to current years' tax positions	8	3
Additions related to prior years' tax positions	0	46
Unrecognized Tax Benefits, Increase Resulting from Acquisition	32	7
Reductions related to prior years' tax positions	(14)	0
Reductions due to lapse of statue of limitations	(2)	(2)
Settlements with tax authorities	(1)	(3)
Ending balance	$ 130	$ 107