Fair Value Election and Measurement Level 3 Significant Unobservable Input Assumptions (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		12 Months Ended
	Mar. 31, 2013		Dec. 31, 2012
level 3 fair value assumptions [Line Items]
Loans Held-for-sale, Fair Value Disclosure	2,672	[1]	$ 3,243	[1]
Fair Value, Measurements, Recurring [Member]
level 3 fair value assumptions [Line Items]
Trading Account Assets, Fair Value Disclosure	6,250		6,049
Loans Held-for-sale, Fair Value Disclosure	2,672		3,243
Residential Mortgage, Loans Held For Sale [Member] | Fair Value, Measurements, Recurring [Member]
level 3 fair value assumptions [Line Items]
Loans Held-for-sale, Fair Value Disclosure	2,357		2,924
Market Approach Valuation Technique [Member] | Mortgage-backed Securities, Issued by Private Enterprises [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
level 3 fair value assumptions [Line Items]
Trading Account Assets, Fair Value Disclosure	1		1
Market Approach Valuation Technique [Member] | Asset-backed Securities [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
level 3 fair value assumptions [Line Items]
Trading Account Assets, Fair Value Disclosure	5		5
Market Approach Valuation Technique [Member] | Loans Held For Investment [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
level 3 fair value assumptions [Line Items]
Loans, Held for Investment, Fair Value Disclosure	18		10
Market Approach Valuation Technique [Member] | Other Assets [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
level 3 fair value assumptions [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset and Liabilities	99	[2]	132	[2]
Market Approach Valuation Technique [Member] | Available-for-sale Securities [Member] | Mortgage-backed Securities, Issued by Private Enterprises [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
level 3 fair value assumptions [Line Items]
Investments, Fair Value Disclosure	202		209
Market Approach Valuation Technique [Member] | Available-for-sale Securities [Member] | Asset-backed Securities [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
level 3 fair value assumptions [Line Items]
Investments, Fair Value Disclosure	23		21
Market Approach Valuation Technique [Member] | Available-for-sale Securities [Member] | US States and Political Subdivisions Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
level 3 fair value assumptions [Line Items]
Investments, Fair Value Disclosure	47		46
Cost Approach Valuation Technique [Member] | Available-for-sale Securities [Member] | Corporate And Other Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
level 3 fair value assumptions [Line Items]
Investments, Fair Value Disclosure	5		5
Cost Approach Valuation Technique [Member] | Available-for-sale Securities [Member] | Equity Securities, Other [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
level 3 fair value assumptions [Line Items]
Investments, Fair Value Disclosure	672		633
Income Approach Valuation Technique [Member] | Collateralized Debt Obligations [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
level 3 fair value assumptions [Line Items]
Trading Account Assets, Fair Value Disclosure	61		52
Income Approach Valuation Technique [Member] | Residential Mortgage, Loans Held For Sale [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
level 3 fair value assumptions [Line Items]
Loans Held-for-sale, Fair Value Disclosure	6		8
Income Approach Valuation Technique [Member] | Loans Held For Investment [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
level 3 fair value assumptions [Line Items]
Loans, Held for Investment, Fair Value Disclosure	342		369
Income Approach Valuation Technique [Member] | Mortgage Servicing Rights [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
level 3 fair value assumptions [Line Items]
Intangible Assets, Fair Value Disclosure	1,025		899
Lower Limit | Market Approach Valuation Technique [Member] | Collateralized Debt Obligations [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
level 3 fair value assumptions [Line Items]
Fair Value Inputs, indicative pricing based on overcollateralization ratio			33
Fair Value Inputs, Estimated Collateral Losses	32.00%		34.00%
Fair Value Inputs, Market Yield	9.00%
Lower Limit | Market Approach Valuation Technique [Member] | Asset-backed Securities [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
level 3 fair value assumptions [Line Items]
Fair Value Inputs, Indicative Pricing	45		45
Lower Limit | Market Approach Valuation Technique [Member] | Other Assets [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
level 3 fair value assumptions [Line Items]
Fair Value Inputs, Pull Through Rate	10.00%		9.00%
Fair Value Inputs, Msr Value	0.10%		0.06%
Lower Limit | Market Approach Valuation Technique [Member] | Available-for-sale Securities [Member] | US States and Political Subdivisions Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
level 3 fair value assumptions [Line Items]
Fair Value Inputs, Indicative Pricing	80		72
Lower Limit | Income Approach Valuation Technique [Member] | Residential Mortgage, Loans Held For Sale [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
level 3 fair value assumptions [Line Items]
Fair Value Inputs, Option Adjusted Spread	1.75%		0.00%
Fair Value Inputs, Conditional Prepayment Rate	3.00%		5.00%
Fair Value Inputs, Probability of Default	0.00%		0.00%
Lower Limit | Income Approach Valuation Technique [Member] | Loans Held For Investment [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
level 3 fair value assumptions [Line Items]
Fair Value Inputs, Option Adjusted Spread	0.00%		0.00%
Fair Value Inputs, Conditional Prepayment Rate	1.00%		5.00%
Fair Value Inputs, Probability of Default	0.00%		0.00%
Lower Limit | Income Approach Valuation Technique [Member] | Mortgage Servicing Rights [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
level 3 fair value assumptions [Line Items]
Fair Value Inputs, Conditional Prepayment Rate	6.00%		6.00%
Fair Value Inputs, Discount Rate	8.00%		9.00%
Lower Limit | Income Approach Valuation Technique [Member] | Other Liabilities [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
level 3 fair value assumptions [Line Items]
fair value inputs, loan production volume	0.00%		0.00%
Upper Limit | Market Approach Valuation Technique [Member] | Collateralized Debt Obligations [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
level 3 fair value assumptions [Line Items]
Fair Value Inputs, indicative pricing based on overcollateralization ratio			45
Fair Value Inputs, Estimated Collateral Losses	45.00%		45.00%
Fair Value Inputs, Market Yield	11.00%
Upper Limit | Market Approach Valuation Technique [Member] | Asset-backed Securities [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
level 3 fair value assumptions [Line Items]
Fair Value Inputs, Indicative Pricing	45		45
Upper Limit | Market Approach Valuation Technique [Member] | Other Assets [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
level 3 fair value assumptions [Line Items]
Fair Value Inputs, Pull Through Rate	98.00%		98.00%
Fair Value Inputs, Msr Value	2.43%		2.44%
Upper Limit | Market Approach Valuation Technique [Member] | Available-for-sale Securities [Member] | US States and Political Subdivisions Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
level 3 fair value assumptions [Line Items]
Fair Value Inputs, Indicative Pricing	115		115
Upper Limit | Income Approach Valuation Technique [Member] | Residential Mortgage, Loans Held For Sale [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
level 3 fair value assumptions [Line Items]
Fair Value Inputs, Option Adjusted Spread	6.25%		6.22%
Fair Value Inputs, Conditional Prepayment Rate	20.00%		30.00%
Fair Value Inputs, Probability of Default	1.00%		20.00%
Upper Limit | Income Approach Valuation Technique [Member] | Loans Held For Investment [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
level 3 fair value assumptions [Line Items]
Fair Value Inputs, Option Adjusted Spread	6.25%		6.22%
Fair Value Inputs, Conditional Prepayment Rate	30.00%		30.00%
Fair Value Inputs, Probability of Default	12.00%		20.00%
Upper Limit | Income Approach Valuation Technique [Member] | Mortgage Servicing Rights [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
level 3 fair value assumptions [Line Items]
Fair Value Inputs, Conditional Prepayment Rate	26.00%		31.00%
Fair Value Inputs, Discount Rate	28.00%		28.00%
Upper Limit | Income Approach Valuation Technique [Member] | Other Liabilities [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
level 3 fair value assumptions [Line Items]
fair value inputs, loan production volume	150.00%		150.00%
Weighted Average [Member] | Market Approach Valuation Technique [Member] | Collateralized Debt Obligations [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
level 3 fair value assumptions [Line Items]
Fair Value Inputs, indicative pricing based on overcollateralization ratio			40
Fair Value Inputs, Estimated Collateral Losses	40.00%		39.00%
Fair Value Inputs, Market Yield	10.00%
Weighted Average [Member] | Market Approach Valuation Technique [Member] | Asset-backed Securities [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
level 3 fair value assumptions [Line Items]
Fair Value Inputs, Indicative Pricing	45		45
Weighted Average [Member] | Market Approach Valuation Technique [Member] | Other Assets [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
level 3 fair value assumptions [Line Items]
Fair Value Inputs, Pull Through Rate	70.00%		71.00%
Fair Value Inputs, Msr Value	1.17%		1.04%
Weighted Average [Member] | Market Approach Valuation Technique [Member] | Available-for-sale Securities [Member] | US States and Political Subdivisions Debt Securities [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
level 3 fair value assumptions [Line Items]
Fair Value Inputs, Indicative Pricing	96		92
Weighted Average [Member] | Income Approach Valuation Technique [Member] | Residential Mortgage, Loans Held For Sale [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
level 3 fair value assumptions [Line Items]
Fair Value Inputs, Option Adjusted Spread	2.52%		2.51%
Fair Value Inputs, Conditional Prepayment Rate	7.00%		15.00%
Fair Value Inputs, Probability of Default	0.50%		3.50%
Weighted Average [Member] | Income Approach Valuation Technique [Member] | Loans Held For Investment [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
level 3 fair value assumptions [Line Items]
Fair Value Inputs, Option Adjusted Spread	2.55%		2.51%
Fair Value Inputs, Conditional Prepayment Rate	15.00%		15.00%
Fair Value Inputs, Probability of Default	3.00%		3.50%
Weighted Average [Member] | Income Approach Valuation Technique [Member] | Mortgage Servicing Rights [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
level 3 fair value assumptions [Line Items]
Fair Value Inputs, Conditional Prepayment Rate	14.00%		16.00%
Fair Value Inputs, Discount Rate	11.00%		11.00%
Weighted Average [Member] | Income Approach Valuation Technique [Member] | Other Liabilities [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
level 3 fair value assumptions [Line Items]
fair value inputs, loan production volume	92.00%		92.00%
Loan Production Volume [Member] | Income Approach Valuation Technique [Member] | Other Liabilities [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
level 3 fair value assumptions [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value	(24)	[2]	(24)	[2]
Revenue Run Rate [Member] | Income Approach Valuation Technique [Member] | Other Liabilities [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Recurring [Member]
level 3 fair value assumptions [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value	(7)	[2]	$ (7)	[2]

[1] 1 Includes loans held for sale, at fair value, of consolidated VIEs315 319

[2] Input assumptions relate to the Company's IRLCs and the contingent consideration obligations related to acquisitions. Refer to Note 11, "Reinsurance Arrangements and Guarantees," for additional information.