Business Segments - Group Reporting Basis to US GAAP Adjustments from previous table (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Debt extinguishment
Segment Reporting Information [Line Items]
Net Interest Income			$ 0
Other Revenues			123
Provision for Credit Losses			0
Operating expenses			0
Profit (Loss) before Income Tax Expense			123
Total assets			0
Deposit incentives
Segment Reporting Information [Line Items]
Net Interest Income	$ 13	$ 14	15
Other Revenues	0	0	0
Provision for Credit Losses	0	0	0
Operating expenses	9	21	32
Profit (Loss) before Income Tax Expense	4	(7)	(17)
Total assets	(25)	(28)	(23)
Derivatives
Segment Reporting Information [Line Items]
Net Interest Income	0	0	0
Other Revenues	0	0	0
Provision for Credit Losses	0	0	0
Operating expenses	0	0	0
Profit (Loss) before Income Tax Expense	0	0	0
Total assets	(16,172)	(33,163)	(38,651)
Expected credit losses
Segment Reporting Information [Line Items]
Net Interest Income	0	(4)	(3)
Other Revenues	0	0	(1)
Provision for Credit Losses	(272)	200	32
Operating expenses	0	0	0
Profit (Loss) before Income Tax Expense	272	(204)	(36)
Total assets	(148)	(357)	(357)
Goodwill
Segment Reporting Information [Line Items]
Net Interest Income	0	0	0
Other Revenues	0	0	0
Provision for Credit Losses	0	0	0
Operating expenses	0	91	156
Profit (Loss) before Income Tax Expense	0	(91)	(156)
Total assets	100	100	191
Leases
Segment Reporting Information [Line Items]
Net Interest Income	16	23	25
Other Revenues	0	0	0
Provision for Credit Losses	0	0	0
Operating expenses	22	14	8
Profit (Loss) before Income Tax Expense	(6)	9	17
Total assets	13	33	15
Loan origination
Segment Reporting Information [Line Items]
Net Interest Income	(11)	(24)	(27)
Other Revenues	0	(2)	0
Provision for Credit Losses	0	0	0
Operating expenses	(20)	(20)	(19)
Profit (Loss) before Income Tax Expense	9	(6)	(8)
Total assets	23	18	38
Loans held for sale
Segment Reporting Information [Line Items]
Net Interest Income	0	0	2
Other Revenues	(31)	(25)	(1)
Provision for Credit Losses	(93)	(12)	0
Operating expenses	0	0	0
Profit (Loss) before Income Tax Expense	62	(13)	1
Total assets	(31)	0	(5)
Other long-lived assets impairment
Segment Reporting Information [Line Items]
Net Interest Income	0	0
Other Revenues	0	0
Provision for Credit Losses	0	0
Operating expenses	61	(264)
Profit (Loss) before Income Tax Expense	(61)	264
Total assets	152	201
Pension and other postretirement benefit costs
Segment Reporting Information [Line Items]
Net Interest Income	0	0	0
Other Revenues	0	0	0
Provision for Credit Losses	0	0	0
Operating expenses	(10)	(15)	(12)
Profit (Loss) before Income Tax Expense	10	15	12
Total assets	0	0	0
Renewable energy tax credit investments
Segment Reporting Information [Line Items]
Net Interest Income	0	0	0
Other Revenues	(21)	(11)	(7)
Provision for Credit Losses	0	0	0
Operating expenses	0	0	0
Profit (Loss) before Income Tax Expense	(21)	(11)	(7)
Total assets	3	2	3
Securities transferred to held-to-maturity
Segment Reporting Information [Line Items]
Net Interest Income	0	0	0
Other Revenues	0	0	0
Provision for Credit Losses	0	0	0
Operating expenses	0	0	0
Profit (Loss) before Income Tax Expense	0	0	0
Total assets	(24)	(38)	(65)
Other
Segment Reporting Information [Line Items]
Net Interest Income	1	0	1
Other Revenues	1	(8)	(12)
Provision for Credit Losses	0	0	0
Operating expenses	0	1	4
Profit (Loss) before Income Tax Expense	2	(9)	(15)
Total assets	(5)	(11)	6
Total adjustments
Segment Reporting Information [Line Items]
Net Interest Income	19	9	13
Other Revenues	(51)	(46)	102
Provision for Credit Losses	(365)	188	32
Operating expenses	62	(172)	169
Profit (Loss) before Income Tax Expense	271	(53)	(86)
Total assets	$ (16,114)	$ (33,243)	$ (38,848)