Investment Securities (Summary) (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale, amortized cost	$ 50,534	$ 48,609
Securities available for sale, unrealized gains	2,147	1,580
Securities available for sale, unrealized losses	(548)	(1,621)
Securities available for sale, fair value	52,133	48,568
Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale, amortized cost	50,213	48,241
Securities available for sale, unrealized gains	2,147	1,580
Securities available for sale, unrealized losses	(548)	(1,621)
Securities available for sale, fair value	51,812	48,200
Held-to-maturity securities, amortized cost	10,681	12,066
Held-to-maturity securities, unrealized gains	553	390
Held-to-maturity securities, unrealized losses	(2)	(6)
Held-to-maturity securities, fair value	11,232	12,450
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale, amortized cost	321	368
Securities available for sale, fair value	321	368
US Treasury and Government Agencies Securities [Member] \| Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale, amortized cost	2,773
Held-to-maturity securities, amortized cost	228
Residential mortgage-backed Securities [Member] \| Mortgage-backed Securities Agency [Member] \| Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale, amortized cost	26,850
Held-to-maturity securities, amortized cost	4,578
Residential mortgage-backed Securities [Member] \| Mortgage-backed Securities Non-agency [Member] \| Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale, amortized cost	6,313
Securities available for sale, unrealized gains		152
Commercial Mortgage Backed Securities [Member] \| Mortgage-backed Securities Agency [Member] \| Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale, amortized cost	616
Held-to-maturity securities, amortized cost	1,292
Commercial Mortgage Backed Securities [Member] \| Mortgage-backed Securities Non-agency [Member] \| Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale, amortized cost	3,088
Held-to-maturity securities, amortized cost	2,784
State and Municipal [Member] \| Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale, amortized cost	1,970
Held-to-maturity securities, amortized cost	671
Other Debt Securities [Member] \| Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale, amortized cost	3,015
Held-to-maturity securities, amortized cost	356
US Treasury and Government Agencies Securities [Member] \| Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale, amortized cost	2,773	3,369
Securities available for sale, unrealized gains	251	348
Securities available for sale, fair value	3,024	3,717
Held-to-maturity securities, amortized cost	228	221
Held-to-maturity securities, unrealized gains	50	40
Held-to-maturity securities, fair value	278	261
Residential mortgage-backed Securities [Member] \| Mortgage-backed Securities Agency [Member] \| Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale, amortized cost	26,850	26,081
Securities available for sale, unrealized gains	1,087	772
Securities available for sale, unrealized losses	(7)	(61)
Securities available for sale, fair value	27,930	26,792
Held-to-maturity securities, amortized cost	4,578	4,761
Held-to-maturity securities, unrealized gains	222	131
Held-to-maturity securities, unrealized losses		(1)
Held-to-maturity securities, fair value	4,800	4,891
Residential mortgage-backed Securities [Member] \| Mortgage-backed Securities Non-agency [Member] \| Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale, amortized cost	6,313	6,673
Securities available for sale, unrealized gains	308
Securities available for sale, unrealized losses	(401)	(1,268)
Securities available for sale, fair value	6,220	5,557
Commercial Mortgage Backed Securities [Member] \| Mortgage-backed Securities Agency [Member] \| Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale, amortized cost	616	1,101
Securities available for sale, unrealized gains	35	39
Securities available for sale, fair value	651	1,140
Held-to-maturity securities, amortized cost	1,292	1,332
Held-to-maturity securities, unrealized gains	88	50
Held-to-maturity securities, fair value	1,380	1,382
Commercial Mortgage Backed Securities [Member] \| Mortgage-backed Securities Non-agency [Member] \| Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale, amortized cost	3,088	2,693
Securities available for sale, unrealized gains	195	80
Securities available for sale, unrealized losses	(2)	(17)
Securities available for sale, fair value	3,281	2,756
Held-to-maturity securities, amortized cost	2,784	3,467
Held-to-maturity securities, unrealized gains	109	108
Held-to-maturity securities, unrealized losses		(2)
Held-to-maturity securities, fair value	2,893	3,573
Asset Backed Securities [Member] \| Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale, amortized cost	5,588	3,854
Securities available for sale, unrealized gains	49	31
Securities available for sale, unrealized losses	(98)	(216)
Securities available for sale, fair value	5,539	3,669
Held-to-maturity securities, amortized cost	772	1,251
Held-to-maturity securities, unrealized gains	5	14
Held-to-maturity securities, unrealized losses	(2)	(3)
Held-to-maturity securities, fair value	775	1,262
State and Municipal [Member] \| Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale, amortized cost	1,970	1,779
Securities available for sale, unrealized gains	114	75
Securities available for sale, unrealized losses	(35)	(47)
Securities available for sale, fair value	2,049	1,807
Held-to-maturity securities, amortized cost	671	671
Held-to-maturity securities, unrealized gains	58	31
Held-to-maturity securities, fair value	729	702
Other Debt Securities [Member] \| Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Securities available for sale, amortized cost	3,015	2,691
Securities available for sale, unrealized gains	108	83
Securities available for sale, unrealized losses	(5)	(12)
Securities available for sale, fair value	3,118	2,762
Held-to-maturity securities, amortized cost	356	363
Held-to-maturity securities, unrealized gains	21	16
Held-to-maturity securities, fair value	$ 377	$ 379

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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-Publisher FASB

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Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

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-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 115

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Reference 9: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 115

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-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

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+ Details

- Definition

This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

+ References+ Details

- Definition

This item represents the gross unrealized gains for securities, at a point in time, which are categorized neither as held-to-maturity nor trading securities.

+ References+ Details

- Definition

For an unclassified balance sheet, this item represents investments in debt securities which are categorized as held-to-maturity. The held-to-maturity category is for those securities that the entity has the positive intent and ability to hold until maturity.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

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-Paragraph 1

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-Publisher AICPA

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Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

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Reference 7: http://www.xbrl.org/2003/role/presentationRef

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Reference 8: http://www.xbrl.org/2003/role/presentationRef

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Reference 10: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

-Name Accounting Research Bulletin (ARB)

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-Paragraph 4

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-Publisher FASB

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Reference 12: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

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-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.6)

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+ Details

- Definition

This item represents the aggregate fair value of investments in debt securities as of the balance sheet date and which are categorized as held-to-maturity.

+ References+ Details

- Definition

As of the balance sheet date, the excess of fair value over carrying value (amortized cost) of a debt security categorized as held-to-maturity, exclusive of dividend or interest income recognized but not yet received and exclusive of any write-downs for other-than-temporary impairment. Such item represents the gross unrecognized holding gain.

+ References+ Details

- Definition

As of the balance sheet date, the excess of carrying value (amortized cost) over fair value of a debt security categorized as held-to-maturity, exclusive of dividend or interest income recognized but not yet received and exclusive of any write-downs for other-than-temporary impairment. Such item represents the gross unrecognized holding loss.

+ References+ Details