Derivative Instruments - Derivatives and Hedges (Details) - Cash Flow Hedges - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020	Sep. 30, 2020
Foreign exchange risk
Derivatives and Hedges
Unrecognized (loss) gain included in Accumulated OCI	$ 9	$ 9	$ 9
Interest rate risk
Derivatives and Hedges
Unrecognized (loss) gain included in Accumulated OCI	$ 0
Interest rate risk | Maximum
Derivatives and Hedges
Unrecognized (loss) gain included in Accumulated OCI		$ (1)	$ (1)