Condensed Consolidated Statement of Income Condensed Consolidated Statement of Income - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Financing Revenue and Other Income [Line Items]
Interest and Fee Income, Loans and Leases	$ 1,447	$ 1,265	$ 2,815	$ 2,500
Interest and Dividend Income, Securities, Operating, Available-for-sale	146	99	280	201
Interest Income, Deposits with Financial Institutions	7	4	12	7
Operating Leases, Income Statement, Lease Revenue	488	701	1,031	1,470
Total financing revenue and other interest income	2,088	2,069	4,138	4,178
Interest Expense [Abstract]
Interest Expense, Deposits	250	203	481	396
Interest Expense, Short-term Borrowings	33	12	60	25
Interest Expense, Long-term Debt	417	436	841	878
Interest Expense	700	651	1,382	1,299
Operating Leases, Income Statement, Depreciation Expense on Property Subject to or Held-for-lease	321	434	710	944
Net Financing Revenue	1,067	984	2,046	1,935
Other revenue [Abstract]
Insurance Services Revenue	227	236	468	466
Gain (Loss) on Sales of Loans, Net	36	3	50	4
Gain (Loss) on Extinguishment of Debt	(1)	0	(2)	(4)
Available-for-sale Securities, Gross Realized Gain (Loss), Excluding Other than Temporary Impairments	23	39	50	93
Noninterest Income, Other Operating Income	103	96	218	191
Nonoperating Income (Expense)	388	374	784	750
Revenues	1,455	1,358	2,830	2,685
Provision for Loan Losses Expensed	269	172	540	392
Noninterest Expense [Abstract]
Labor and Related Expense	265	242	550	494
Liability for Unpaid Claims and Claims Adjustment Expense, Incurred Claims	125	145	213	218
Other Noninterest Expense	420	386	825	771
Noninterest Expense	810	773	1,588	1,483
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest	376	413	702	810
Income Tax Expense (Benefit)	122	56	235	206
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent	254	357	467	604
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	(2)	3	(1)	6
Net Income (Loss) Attributable to Parent	252	360	466	610
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	76	120	96	266
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	$ 328	$ 480	$ 562	$ 876
Earnings Per Share, Basic [Abstract]
Income (Loss) from Continuing Operations, Per Basic Share	$ 0.55	$ 0.70	$ 1.01	$ 1.18
Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Basic Share	(0.01)	0.01	0.00	0.01
Earnings Per Share, Basic	0.55	0.71	1.01	1.20
Earnings Per Share, Diluted [Abstract]
Income (Loss) from Continuing Operations, Per Diluted Share	0.55	0.70	1.01	1.18
Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Diluted Share	(0.01)	0.01	0.00	0.01
Earnings Per Share, Diluted	0.55	0.71	1.01	1.19
Common Stock, Dividends, Per Share, Declared	$ 0.08	$ 0.00	$ 0.16	$ 0.00
Retained Earnings [Member]
Net Income (Loss) Attributable to Parent	$ 252	$ 360	$ 466	$ 610