Derivatives - Offsetting Liabilities (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Offsetting of Financial Liabilities under Master Netting Agreements with Derivative Counterparties
Gross Amounts of Derivative Liabilities Presented in the Consolidated Balance Sheet	$ 46	$ 20
Net Amount of Derivative Liabilities	19	6
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	46	20
Gross Amount of Eligible Offsetting Recognized Derivative Assets	27	14
Net Amount of Derivative Liabilities	$ 19	$ 6