Components of Other Comprehensive Income (Loss) - Schedule of Reclassification from AOCI (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Realized (gains) losses on cash flow hedges	$ 1,957	$ 1,722	$ 1,394
Amortization of prior service cost and net actuarial (gain) loss	193	141	114
Income tax expense	274	76	134
Total reclassification from AOCI	(1,010)	(857)	(452)
Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Total reclassification from AOCI	1	7	11
Reclassification out of Accumulated Other Comprehensive Income | Securities AFS
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Realized (gains) losses on securities AFS	0	4	0
Income tax expense	0	(1)	0
Total reclassification from AOCI	0	3	0
Reclassification out of Accumulated Other Comprehensive Income | Cash Flow Hedges
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Realized (gains) losses on cash flow hedges	(9)	(8)	5
Income tax expense	2	2	(1)
Total reclassification from AOCI	(7)	(6)	4
Reclassification out of Accumulated Other Comprehensive Income | Pension and Post-retirement Plans
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives [Line Items]
Amortization of prior service cost and net actuarial (gain) loss	10	13	10
Income tax expense	(2)	(3)	(3)
Total reclassification from AOCI	$ 8	$ 10	$ 7