Income Taxes (Operating Loss Carryforwards Narrative) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2019 USD ($)
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards, valuation allowance	$ 1,000
Federal [Member]
Operating Loss Carryforwards [Line Items]
Net operating loss and credit carryforwards	662
Operating loss carryforwards expected to be utilized	169
State and Local Jurisdiction [Member]
Operating Loss Carryforwards [Line Items]
Net operating loss and credit carryforwards	8,600
Operating loss carryforwards expected to be utilized	$ 606
Minimum [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards, expiration date	Jan. 01, 2020
Maximum [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards, expiration date	Dec. 31, 2039