Condensed Consolidated Balance Sheet & Mini Balance Sheet - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016
Assets [Abstract]
Cash and Due from Banks	$ 810	$ 1,547
Interest-bearing Deposits in Banks and Other Financial Institutions	3,614	4,387
Cash and Cash Equivalents, at Carrying Value	4,424	5,934
Available-for-sale securities	23,099	18,926
Held-to-maturity securities	1,839	839
Loans Receivable Held-for-sale, Net, Not Part of Disposal Group	18	0
Finance receivables and loans, net [Abstract]
Loans and Leases Receivable, Gross	118,871	118,944
Financing Receivable, Allowance for Credit Losses	1,286	1,144
Loans and Leases Receivable, Net Amount	117,585	117,800
Property Subject to or Available for Operating Lease, Net	8,931	11,470
Premiums receivable and other insurance assets	2,054	1,905
Other Assets	6,063	6,854
Assets	164,013	163,728
Liabilities and Equity [Abstract]
Noninterest-bearing deposit liabilities	129	84
Interest-bearing Deposit Liabilities	89,987	78,938
Deposits	90,116	79,022
Short-term Debt	10,175	12,673
Long-term Debt	45,122	54,128
Interest payable	552	351
Unearned Premiums	2,583	2,500
Accounts Payable and Accrued Liabilities	1,892	1,737
Liabilities	150,440	150,411
Equity [Abstract]
Common Stocks, Including Additional Paid in Capital, Net of Discount	21,223	21,166
Retained Earnings (Accumulated Deficit)	(6,533)	(7,151)
Accumulated Other Comprehensive Income (Loss), Net of Tax	(197)	(341)
Treasury stock, Value	(920)	(357)
Stockholders' Equity Attributable to Parent, Total	13,573	13,317
Liabilities and Equity	164,013	163,728
Variable Interest Entity, Primary Beneficiary [Member]
Finance receivables and loans, net [Abstract]
Loans and Leases Receivable, Gross	20,020	24,630
Financing Receivable, Allowance for Credit Losses	134	173
Loans and Leases Receivable, Net Amount	19,886	24,457
Property Subject to or Available for Operating Lease, Net	704	1,745
Other Assets	1,037	1,390
Assets	21,627	27,592
Liabilities and Equity [Abstract]
Long-term Debt	10,046	13,259
Accounts Payable and Accrued Liabilities	10	12
Liabilities	$ 10,056	$ 13,271