Income Taxes - Tax Effected Operating Loss, Capital Loss, and Tax Credit Carryovers (Details) $ in Millions	12 Months Ended
	Dec. 31, 2020 USD ($)
Federal jurisdiction
Tax effected operating loss, capital loss, and tax credit carryovers
Tax effected operating loss, capital loss, and tax credit carryovers	$ 108
Federal jurisdiction | Maximum
Tax effected operating loss, capital loss, and tax credit carryovers
Tax effected operating loss, capital loss, and tax credit carryovers, expiration date	10 years
Federal jurisdiction | Minimum
Tax effected operating loss, capital loss, and tax credit carryovers
Tax effected operating loss, capital loss, and tax credit carryovers, expiration date	1 year
State jurisdiction
Tax effected operating loss, capital loss, and tax credit carryovers
Tax effected operating loss, capital loss, and tax credit carryovers	$ 84
State jurisdiction | Maximum
Tax effected operating loss, capital loss, and tax credit carryovers
Tax effected operating loss, capital loss, and tax credit carryovers, expiration date	11 years
State jurisdiction | Minimum
Tax effected operating loss, capital loss, and tax credit carryovers
Tax effected operating loss, capital loss, and tax credit carryovers, expiration date	1 year
International jurisdiction
Tax effected operating loss, capital loss, and tax credit carryovers
Tax effected operating loss, capital loss, and tax credit carryovers	$ 58
International jurisdiction | Minimum
Tax effected operating loss, capital loss, and tax credit carryovers
Tax effected operating loss, capital loss, and tax credit carryovers, expiration date	1 year