Fair Value (Fair Value Option - Summary Of Changes Included In The Condensed Consolidated Statement Of Income) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value, Option, Changes in Fair Value, Gain (Loss)	$ 350	$ 1,067
Mortgage Loans Held-For-Sale [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value, Option, Changes in Fair Value, Gain (Loss)	344	1,084
Fair Value, Option, Credit Risk, Gains (Losses) on Assets	0	0
Mortgage Loans Held-For-Sale [Member] | Interest and fees on finance receivables and loans [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value, Option, Changes in Fair Value, Gain (Loss)	0	0
Mortgage Loans Held-For-Sale [Member] | Interest on loans held-for-sale [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value, Option, Changes in Fair Value, Gain (Loss)	82	176
Mortgage Loans Held-For-Sale [Member] | Interest on long-term debt [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value, Option, Changes in Fair Value, Gain (Loss)	0	0
Mortgage Loans Held-For-Sale [Member] | Gain on mortgage loans, net [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value, Option, Changes in Fair Value, Gain (Loss)	262	908
Mortgage Loans Held-For-Sale [Member] | Other Income [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value, Option, Changes in Fair Value, Gain (Loss)	0	0
Consumer Mortgage Finance Receivables And Loans, Net [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value, Option, Changes in Fair Value, Gain (Loss)	121	353
Fair Value, Option, Credit Risk, Gains (Losses) on Assets	(24)	(119)
Consumer Mortgage Finance Receivables And Loans, Net [Member] | Interest and fees on finance receivables and loans [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value, Option, Changes in Fair Value, Gain (Loss)	59	200
Consumer Mortgage Finance Receivables And Loans, Net [Member] | Interest on loans held-for-sale [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value, Option, Changes in Fair Value, Gain (Loss)	0	0
Consumer Mortgage Finance Receivables And Loans, Net [Member] | Interest on long-term debt [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value, Option, Changes in Fair Value, Gain (Loss)	0	0
Consumer Mortgage Finance Receivables And Loans, Net [Member] | Gain on mortgage loans, net [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value, Option, Changes in Fair Value, Gain (Loss)	0	0
Consumer Mortgage Finance Receivables And Loans, Net [Member] | Other Income [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value, Option, Changes in Fair Value, Gain (Loss)	62	153
On-Balance Sheet Securitization Debt [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value, Option, Changes in Fair Value, Gain (Loss)	(115)	(372)
Fair Value, Option, Credit Risk, Gains (Losses) on Liabilities	(8)	(20)
On-Balance Sheet Securitization Debt [Member] | Interest and fees on finance receivables and loans [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value, Option, Changes in Fair Value, Gain (Loss)	0	0
On-Balance Sheet Securitization Debt [Member] | Interest on loans held-for-sale [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value, Option, Changes in Fair Value, Gain (Loss)	0	0
On-Balance Sheet Securitization Debt [Member] | Interest on long-term debt [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value, Option, Changes in Fair Value, Gain (Loss)	(34)	(116)
On-Balance Sheet Securitization Debt [Member] | Gain on mortgage loans, net [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value, Option, Changes in Fair Value, Gain (Loss)	0	0
On-Balance Sheet Securitization Debt [Member] | Other Income [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value, Option, Changes in Fair Value, Gain (Loss)	(81)	(256)
Loan repurchase liabilities [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value, Option, Changes in Fair Value, Gain (Loss)		2
Fair Value, Option, Credit Risk, Gains (Losses) on Liabilities		0
Loan repurchase liabilities [Member] | Interest and fees on finance receivables and loans [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value, Option, Changes in Fair Value, Gain (Loss)		0
Loan repurchase liabilities [Member] | Interest on loans held-for-sale [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value, Option, Changes in Fair Value, Gain (Loss)		0
Loan repurchase liabilities [Member] | Interest on long-term debt [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value, Option, Changes in Fair Value, Gain (Loss)		0
Loan repurchase liabilities [Member] | Gain on mortgage loans, net [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value, Option, Changes in Fair Value, Gain (Loss)		0
Loan repurchase liabilities [Member] | Other Income [Member]
Fair Value, Option, Quantitative Disclosures [Line Items]
Fair Value, Option, Changes in Fair Value, Gain (Loss)		$ 2