Income Taxes - Allocation of Income Tax Expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income tax expense in the consolidated statements of operations:
Attributable to income	$ 221	$ 255	$ 196
Member's equity:
Tax effect of the change in accumulated other comprehensive loss	$ 43	$ 5	$ (49)