Income Taxes (Unrecognized Tax Benefits Information) (Details 4) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Operating Loss Carryforwards [Line Items]
Deferred Tax Assets, Operating Loss Carryforwards	$ 16
Unrecognized tax benefits, net of federal tax benefits, that would impact the effective tax rate	67	$ 70	$ 58
Increase (decrease) in interest and penalties	2	2	0
Payable related to accrued interest and penalties	8	10
Reconciliation of gross unrecognized tax benefits (expense)
Beginning balance	92	76	115
Additions based on tax positions related to the current year	15	22	16
Additions for tax positions of prior years	39	9	3
Reductions for tax positions of prior years	(17)	(3)	(57)
Unrecognized Tax Benefits, Decrease Resulting from Settlements with Taxing Authorities	(29)	(12)	(1)
Ending balance	100	$ 92	$ 76
Minimum [Member]
Operating Loss Carryforwards [Line Items]
Decrease in gross amount of unrecognized tax benefits due to resolution of IRS examinations	40
Maximum [Member]
Operating Loss Carryforwards [Line Items]
Decrease in gross amount of unrecognized tax benefits due to resolution of IRS examinations	50
State and Local Jurisdiction [Member]
Operating Loss Carryforwards [Line Items]
Operating Loss Carryforwards, Valuation Allowance	$ 13