Income Taxes (Summary of Operating Losses and Tax Credits) (Details) $ in Millions	Dec. 31, 2020 USD ($)
United States
Operating Loss Carryforwards [Line Items]
Net operating loss	$ 7
State
Operating Loss Carryforwards [Line Items]
Net operating loss	97
Tax credits	1
Foreign
Operating Loss Carryforwards [Line Items]
Net operating loss	1,153
Tax credits	4
Excess Interest Expense | State
Operating Loss Carryforwards [Line Items]
Tax credits	$ 10