Condensed Consolidated Statement of Income Condensed Consolidated Statement of Income - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Financing Revenue and Other Income [Line Items]
Interest and Fee Income, Loans and Leases	$ 1,486	$ 1,307	$ 4,301	$ 3,807
Interest and Dividend Income, Securities, Operating, Available-for-sale	157	101	437	302
Interest Income, Deposits with Financial Institutions	11	3	23	10
Operating Leases, Income Statement, Lease Revenue	434	649	1,465	2,119
Total financing revenue and other interest income	2,088	2,060	6,226	6,238
Interest Expense [Abstract]
Interest Expense, Deposits	285	212	766	608
Interest Expense, Short-term Borrowings	34	14	94	39
Interest Expense, Long-term Debt	416	430	1,257	1,308
Interest Expense	735	656	2,117	1,955
Operating Leases, Income Statement, Depreciation Expense on Property Subject to or Held-for-lease	272	408	982	1,352
Net Financing Revenue	1,081	996	3,127	2,931
Other revenue [Abstract]
Insurance Services Revenue	252	238	720	704
Gain (Loss) on Sales of Loans, Net	15	0	65	4
Gain (Loss) on Extinguishment of Debt	(4)	0	(6)	(4)
Available-for-sale Securities, Gross Realized Gain (Loss), Excluding Other than Temporary Impairments	23	52	73	145
Noninterest Income, Other Operating Income	95	98	313	289
Nonoperating Income (Expense)	381	388	1,165	1,138
Revenues	1,462	1,384	4,292	4,069
Provision for Loan Losses Expensed	314	258	854	650
Noninterest Expense [Abstract]
Labor and Related Expense	264	248	814	742
Liability for Unpaid Claims and Claims Adjustment Expense, Incurred Claims	65	69	278	287
Other Noninterest Expense	424	418	1,249	1,189
Noninterest Expense	753	735	2,341	2,218
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Noncontrolling Interest	395	391	1,097	1,201
Income Tax Expense (Benefit)	115	130	350	336
Income (Loss) from Continuing Operations, Net of Tax, Attributable to Parent	280	261	747	865
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	2	(52)	1	(46)
Net Income (Loss) Attributable to Parent	282	209	748	819
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	48	(4)	144	262
Comprehensive Income (Loss), Net of Tax, Attributable to Parent	$ 330	$ 205	$ 892	$ 1,081
Earnings Per Share, Basic [Abstract]
Income (Loss) from Continuing Operations, Per Basic Share	$ 0.62	$ 0.54	$ 1.63	$ 1.73
Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Basic Share	0.00	(0.11)	0.00	(0.10)
Earnings Per Share, Basic	0.63	0.43	1.63	1.63
Earnings Per Share, Diluted [Abstract]
Income (Loss) from Continuing Operations, Per Diluted Share	0.62	0.54	1.63	1.72
Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Diluted Share	0.00	(0.11)	0.00	(0.10)
Earnings Per Share, Diluted	0.63	0.43	1.63	1.63
Common Stock, Dividends, Per Share, Declared	$ 0.12	$ 0.08	$ 0.28	$ 0.08
Retained Earnings [Member]
Net Income (Loss) Attributable to Parent	$ 282	$ 209	$ 748	$ 819