Fair Value, Assets and Liabilities Measured on a Recurring Basis Level 3 Valuation Techniques and Significant Unobservable Inputs (Details) $ in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2015 USD ($) $ / loan	Dec. 31, 2014 USD ($) $ / loan
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Mortgages held for sale, carried at fair value	$ 21,539	$ 15,565
Loans	5,651	5,788
Mortgage servicing rights	12,661	12,738
Fair Value Inputs [Abstract]
Aggregate Fair Value Of Derivative Loan Commitments Net Asset (Liability)	$ 36	$ 98
Interest rate contract [Member] | Minimum [Member] | Discounted cash flow [Member]
Fair Value Inputs [Abstract]
Loss severity	50.00%	50.00%
Default rate	0.00%	0.00%
Interest rate contract [Member] | Maximum [Member] | Discounted cash flow [Member]
Fair Value Inputs [Abstract]
Loss severity	50.00%	50.00%
Default rate	0.07%	0.02%
Interest rate contract [Member] | Weighted Average [Member] | Discounted cash flow [Member]
Fair Value Inputs [Abstract]
Loss severity	50.00%	50.00%
Default rate	0.03%	0.01%
Derivative loan commitments [Member] | Minimum [Member] | Discounted cash flow [Member]
Fair Value Inputs [Abstract]
Fall-out factor	1.00%	1.00%
Initial-value servicing (in bps)	(0.315%)	(0.311%)
Derivative loan commitments [Member] | Maximum [Member] | Discounted cash flow [Member]
Fair Value Inputs [Abstract]
Fall-out factor	99.00%	99.00%
Initial-value servicing (in bps)	1.25%	1.133%
Derivative loan commitments [Member] | Weighted Average [Member] | Discounted cash flow [Member]
Fair Value Inputs [Abstract]
Fall-out factor	21.40%	24.50%
Initial-value servicing (in bps)	0.485%	0.465%
Equity contract [Member] | Minimum [Member] | Discounted cash flow [Member]
Fair Value Inputs [Abstract]
Weighted average life	1 year	1 year
Conversion factor	(11.10%)	(11.20%)
Equity contract [Member] | Minimum [Member] | Option model [Member]
Fair Value Inputs [Abstract]
Volatility factor	8.30%	8.30%
Correlation factor	(50.00%)	(56.00%)
Equity contract [Member] | Maximum [Member] | Discounted cash flow [Member]
Fair Value Inputs [Abstract]
Weighted average life	2 years 5 months 30 days	2 years
Conversion factor	0.00%	0.00%
Equity contract [Member] | Maximum [Member] | Option model [Member]
Fair Value Inputs [Abstract]
Volatility factor	69.40%	80.90%
Correlation factor	96.30%	96.30%
Equity contract [Member] | Weighted Average [Member] | Discounted cash flow [Member]
Fair Value Inputs [Abstract]
Weighted average life	1 year 8 months 11 days	1 year 3 months 18 days
Conversion factor	(8.20%)	(8.40%)
Equity contract [Member] | Weighted Average [Member] | Option model [Member]
Fair Value Inputs [Abstract]
Volatility factor	22.50%	28.30%
Correlation factor	55.90%	42.10%
Credit contract [Member] | Minimum [Member] | Market comparable pricing [Member]
Fair Value Inputs [Abstract]
Comparability adjustment	(29.60%)	(28.60%)
Credit contract [Member] | Minimum [Member] | Option model [Member]
Fair Value Inputs [Abstract]
Loss severity	11.50%	11.50%
Credit spread	0.00%	0.00%
Credit contract [Member] | Maximum [Member] | Market comparable pricing [Member]
Fair Value Inputs [Abstract]
Comparability adjustment	32.00%	26.30%
Credit contract [Member] | Maximum [Member] | Option model [Member]
Fair Value Inputs [Abstract]
Loss severity	72.00%	72.50%
Credit spread	16.50%	17.00%
Credit contract [Member] | Weighted Average [Member] | Market comparable pricing [Member]
Fair Value Inputs [Abstract]
Comparability adjustment	1.80%	1.80%
Credit contract [Member] | Weighted Average [Member] | Option model [Member]
Fair Value Inputs [Abstract]
Loss severity	51.90%	48.70%
Credit spread	1.10%	0.90%
Government, healthcare and other revenue bonds [Member] | Minimum [Member] | Discounted cash flow [Member]
Fair Value Inputs [Abstract]
Discount rate	0.50%	0.40%
Government, healthcare and other revenue bonds [Member] | Maximum [Member] | Discounted cash flow [Member]
Fair Value Inputs [Abstract]
Discount rate	6.20%	5.60%
Government, healthcare and other revenue bonds [Member] | Weighted Average [Member] | Discounted cash flow [Member]
Fair Value Inputs [Abstract]
Discount rate	1.60%	1.50%
Auction rate and other municipal bonds [Member] | Minimum [Member] | Discounted cash flow [Member]
Fair Value Inputs [Abstract]
Discount rate	2.10%	1.50%
Weighted average life	1 year 8 months 11 days	1 year 3 months 18 days
Auction rate and other municipal bonds [Member] | Maximum [Member] | Discounted cash flow [Member]
Fair Value Inputs [Abstract]
Discount rate	6.00%	7.60%
Weighted average life	10 years 2 months 13 days	19 years 4 months 24 days
Auction rate and other municipal bonds [Member] | Weighted Average [Member] | Discounted cash flow [Member]
Fair Value Inputs [Abstract]
Discount rate	4.00%	3.90%
Weighted average life	4 years 5 months 30 days	6 years 4 months 24 days
Collateralized loan and other debt obligations [Member] | Minimum [Member] | Market comparable pricing [Member]
Fair Value Inputs [Abstract]
Comparability adjustment	(18.10%)	(53.90%)
Collateralized loan and other debt obligations [Member] | Maximum [Member] | Market comparable pricing [Member]
Fair Value Inputs [Abstract]
Comparability adjustment	20.50%	25.00%
Collateralized loan and other debt obligations [Member] | Weighted Average [Member] | Market comparable pricing [Member]
Fair Value Inputs [Abstract]
Comparability adjustment	2.80%	0.90%
Auto loans and leases [Member] | Minimum [Member] | Discounted cash flow [Member]
Fair Value Inputs [Abstract]
Discount rate	(0.50%)	0.40%
Auto loans and leases [Member] | Maximum [Member] | Discounted cash flow [Member]
Fair Value Inputs [Abstract]
Discount rate	(0.50%)	0.40%
Auto loans and leases [Member] | Weighted Average [Member] | Discounted cash flow [Member]
Fair Value Inputs [Abstract]
Discount rate	(0.50%)	0.40%
Diversified payment rights [Member] | Minimum [Member] | Discounted cash flow [Member]
Fair Value Inputs [Abstract]
Discount rate	0.90%	0.90%
Diversified payment rights [Member] | Maximum [Member] | Discounted cash flow [Member]
Fair Value Inputs [Abstract]
Discount rate	5.60%	7.10%
Diversified payment rights [Member] | Weighted Average [Member] | Discounted cash flow [Member]
Fair Value Inputs [Abstract]
Discount rate	2.60%	2.90%
Other commercial and consumer [Member] | Minimum [Member] | Discounted cash flow [Member]
Fair Value Inputs [Abstract]
Discount rate	2.60%	1.90%
Weighted average life	1 year 3 months 18 days	1 year 7 months 6 days
Other commercial and consumer [Member] | Maximum [Member] | Discounted cash flow [Member]
Fair Value Inputs [Abstract]
Discount rate	5.90%	21.50%
Weighted average life	8 years 1 day	10 years 8 months 12 days
Other commercial and consumer [Member] | Weighted Average [Member] | Discounted cash flow [Member]
Fair Value Inputs [Abstract]
Discount rate	3.90%	5.00%
Weighted average life	3 years 10 months 23 days	4 years
Perpetual preferred securities [Member] | Minimum [Member] | Discounted cash flow [Member]
Fair Value Inputs [Abstract]
Discount rate		4.10%
Weighted average life		1 year
Perpetual preferred securities [Member] | Maximum [Member] | Discounted cash flow [Member]
Fair Value Inputs [Abstract]
Discount rate		9.30%
Weighted average life		11 years 9 months 18 days
Perpetual preferred securities [Member] | Weighted Average [Member] | Discounted cash flow [Member]
Fair Value Inputs [Abstract]
Discount rate		6.60%
Weighted average life		9 years 8 months 12 days
Mortgages held for sale [Member] | Minimum [Member] | Discounted cash flow [Member]
Fair Value Inputs [Abstract]
Discount rate	1.10%	1.10%
Prepayment rate	2.00%	2.00%
Loss severity	0.00%	0.10%
Default rate	0.60%	0.40%
Mortgages held for sale [Member] | Minimum [Member] | Market comparable pricing [Member]
Fair Value Inputs [Abstract]
Comparability adjustment	(65.80%)	(93.00%)
Mortgages held for sale [Member] | Maximum [Member] | Discounted cash flow [Member]
Fair Value Inputs [Abstract]
Discount rate	6.30%	7.70%
Prepayment rate	18.50%	15.50%
Loss severity	24.40%	26.40%
Default rate	14.00%	15.00%
Mortgages held for sale [Member] | Maximum [Member] | Market comparable pricing [Member]
Fair Value Inputs [Abstract]
Comparability adjustment	2.70%	10.00%
Mortgages held for sale [Member] | Weighted Average [Member] | Discounted cash flow [Member]
Fair Value Inputs [Abstract]
Discount rate	4.60%	5.20%
Prepayment rate	8.40%	8.10%
Loss severity	14.40%	18.30%
Default rate	2.80%	2.60%
Mortgages held for sale [Member] | Weighted Average [Member] | Market comparable pricing [Member]
Fair Value Inputs [Abstract]
Comparability adjustment	(27.20%)	(30.00%)
Loans [Member] | Minimum [Member] | Discounted cash flow [Member]
Fair Value Inputs [Abstract]
Discount rate	0.00%	0.00%
Prepayment rate	0.50%	0.60%
Utilization rate	0.00%	0.00%
Loans [Member] | Maximum [Member] | Discounted cash flow [Member]
Fair Value Inputs [Abstract]
Discount rate	3.80%	3.80%
Prepayment rate	100.00%	100.00%
Utilization rate	1.00%	1.00%
Loans [Member] | Weighted Average [Member] | Discounted cash flow [Member]
Fair Value Inputs [Abstract]
Discount rate	3.00%	3.10%
Prepayment rate	13.80%	11.20%
Utilization rate	0.40%	0.40%
Residential mortgage servicing rights [Member] | Minimum [Member] | Discounted cash flow [Member]
Fair Value Inputs [Abstract]
Discount rate	6.30%	5.90%
Prepayment rate	8.10%	8.00%
Cost to service per loan | $ / loan	68	86
Residential mortgage servicing rights [Member] | Maximum [Member] | Discounted cash flow [Member]
Fair Value Inputs [Abstract]
Discount rate	12.10%	16.90%
Prepayment rate	23.20%	22.00%
Cost to service per loan | $ / loan	649	683
Residential mortgage servicing rights [Member] | Weighted Average [Member] | Discounted cash flow [Member]
Fair Value Inputs [Abstract]
Discount rate	7.40%	7.60%
Prepayment rate	11.60%	12.50%
Cost to service per loan | $ / loan	169	179
Other assets: nonmarketable equity investments [Member] | Minimum [Member] | Market comparable pricing [Member]
Fair Value Inputs [Abstract]
Comparability adjustment	(21.10%)	(19.70%)
Other assets: nonmarketable equity investments [Member] | Maximum [Member] | Market comparable pricing [Member]
Fair Value Inputs [Abstract]
Comparability adjustment	(4.00%)	(4.00%)
Other assets: nonmarketable equity investments [Member] | Weighted Average [Member] | Market comparable pricing [Member]
Fair Value Inputs [Abstract]
Comparability adjustment	(15.70%)	(14.70%)
Recurring [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Financial and Nonfinancial Liabilities, Fair Value Disclosure	$ (30,629)	$ (34,866)
Mortgages held for sale, carried at fair value	21,539	15,565
Loans	5,651	5,788
Mortgage servicing rights	12,661	12,738
Fair Value, Inputs, Level 3 [Member] | Recurring [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Financial and Nonfinancial Liabilities, Fair Value Disclosure	(2,000)	(2,270)
Mortgages held for sale, carried at fair value	1,623	2,313
Loans	5,651	5,788
Mortgage servicing rights	12,661	12,738
Total insignificant level 3 assets, net of liabilities	542	507
Total level 3 assets, net of liabilities	27,871	30,054
Fair Value, Inputs, Level 3 [Member] | Recurring [Member] | Interest rate contract [Member] | Discounted cash flow [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Net derivative assets and liabilities	211	196
Fair Value, Inputs, Level 3 [Member] | Recurring [Member] | Derivative loan commitments [Member] | Discounted cash flow [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Net derivative assets and liabilities	41	97
Fair Value, Inputs, Level 3 [Member] | Recurring [Member] | Equity contract [Member] | Discounted cash flow [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Net derivative assets and liabilities	99	162
Fair Value, Inputs, Level 3 [Member] | Recurring [Member] | Equity contract [Member] | Option model [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Net derivative assets and liabilities	(284)	(246)
Fair Value, Inputs, Level 3 [Member] | Recurring [Member] | Credit contract [Member] | Market comparable pricing [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Net derivative assets and liabilities	(122)	(192)
Fair Value, Inputs, Level 3 [Member] | Recurring [Member] | Credit contract [Member] | Option model [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Net derivative assets and liabilities	5	3
Fair Value, Inputs, Level 3 [Member] | Recurring [Member] | Government, healthcare and other revenue bonds [Member] | Discounted cash flow [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Trading and available for sale securities	1,587	1,900
Fair Value, Inputs, Level 3 [Member] | Recurring [Member] | Government, healthcare and other revenue bonds [Member] | Vendor priced [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Trading and available for sale securities	53	61
Fair Value, Inputs, Level 3 [Member] | Recurring [Member] | Auction rate and other municipal bonds [Member] | Discounted cash flow [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Trading and available for sale securities	257	323
Fair Value, Inputs, Level 3 [Member] | Recurring [Member] | Collateralized loan and other debt obligations [Member] | Market comparable pricing [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Trading and available for sale securities	480	565
Fair Value, Inputs, Level 3 [Member] | Recurring [Member] | Collateralized loan and other debt obligations [Member] | Vendor priced [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Trading and available for sale securities	851	967
Fair Value, Inputs, Level 3 [Member] | Recurring [Member] | Auto loans and leases [Member] | Discounted cash flow [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Trading and available for sale securities	260	245
Fair Value, Inputs, Level 3 [Member] | Recurring [Member] | Diversified payment rights [Member] | Discounted cash flow [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Trading and available for sale securities	579	661
Fair Value, Inputs, Level 3 [Member] | Recurring [Member] | Other commercial and consumer [Member] | Discounted cash flow [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Trading and available for sale securities	704	750
Fair Value, Inputs, Level 3 [Member] | Recurring [Member] | Other commercial and consumer [Member] | Vendor priced [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Trading and available for sale securities	37	40
Fair Value, Inputs, Level 3 [Member] | Recurring [Member] | Perpetual preferred securities [Member] | Discounted cash flow [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Trading and available for sale securities		663
Fair Value, Inputs, Level 3 [Member] | Recurring [Member] | Mortgages held for sale [Member] | Discounted cash flow [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Mortgages held for sale, carried at fair value	1,550	2,235
Fair Value, Inputs, Level 3 [Member] | Recurring [Member] | Mortgages held for sale [Member] | Market comparable pricing [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Mortgages held for sale, carried at fair value	73	78
Fair Value, Inputs, Level 3 [Member] | Recurring [Member] | Loans [Member] | Discounted cash flow [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Loans	5,651	5,788
Fair Value, Inputs, Level 3 [Member] | Recurring [Member] | Residential mortgage servicing rights [Member] | Discounted cash flow [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Mortgage servicing rights	12,661	12,738
Fair Value, Inputs, Level 3 [Member] | Recurring [Member] | Other assets: nonmarketable equity investments [Member] | Market comparable pricing [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Other assets: nonmarketable equity investments	2,636	2,512
Fair Value, Inputs, Level 2 [Member] | Derivative [Member]
Fair Value Inputs [Abstract]
Aggregate Fair Value Of Derivative Loan Commitments Net Asset (Liability)	(5)
Fair Value, Inputs, Level 2 [Member] | Recurring [Member]
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Financial and Nonfinancial Liabilities, Fair Value Disclosure	(83,309)	(86,958)
Mortgages held for sale, carried at fair value	19,916	13,252
Loans	0	0
Mortgage servicing rights	$ 0	$ 0