Income Taxes Income Taxes - Reconciliation of Unrecognized Tax Benefits (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Reconciliation of Unrecognized Tax Benefits [Line Items]
AACNetTaxableIncomeFromTierB	$ 1,029
Unrecognized Tax Benefits, Interest on Income Taxes Accrued	0	$ 0	$ 0
Reconciliation of Unrecognized Tax Benefits [Roll Forward]
Unrecognized Tax Benefits	0	0	0
Unrecognized Tax Benefits, Increase Resulting from Prior Period Tax Positions	0	0	0
Unrecognized Tax Benefits, Decrease Resulting from Prior Period Tax Positions	0	0	0
Unrecognized Tax Benefits	0	0	0
UnrecognizedTaxBenefitsInterestOnIncomeTaxesPaid	$ 0	$ 0	$ 0