Income Taxes - Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Provisional benefit of revaluation of net DTL due to TCJA			$ 1,500
Benefit of revaluation of net DTL due to TCJA		$ 100
Net operating loss and capital loss carryforwards	$ 480	529
Valuation allowance	374	520
Income tax penalties and interest expense	49	19	$ 11
Income tax penalties and interest accrued	173	$ 80
Unrecognized tax benefits that would impact effective tax rate	$ 532