Derivative Instruments and Hedging Activities - Amounts Reclassified from AOCI (Details) - Interest rate contracts - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Amount of Gain (Loss) Recognized in OCI on Derivatives	$ (51,000,000)	$ (22,000,000)	$ (3,000,000)
Amount of Gain (Loss) Reclassified from AOCI into Income	0	0
Interest income (expense)
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Amount of Gain (Loss) Reclassified from AOCI into Income	(14,000,000)	2,000,000	2,000,000
Other income
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Amount of Gain (Loss) Reclassified from AOCI into Income	$ (9,000,000)	$ 0	$ 0