Derivatives - Offsetting Liabilities (Details) - USD ($) $ in Millions	Mar. 31, 2021	Dec. 31, 2020
Offsetting of Financial Liabilities under Master Netting Agreements with Derivative Counterparties
Gross Amounts of Derivative Liabilities Presented in the Consolidated Balance Sheet	$ 63	$ 106
Net Amount of Derivative Liabilities	29	95
Derivatives subject to master netting agreements
Offsetting of Financial Liabilities under Master Netting Agreements with Derivative Counterparties
Gross Amounts of Derivative Liabilities Presented in the Consolidated Balance Sheet	63	106
Gross Amount of Eligible Offsetting Recognized Derivative Assets	34	11
Net Amount of Derivative Liabilities	$ 29	$ 95