Fair Value Measurements - Carrying and Estimated Fair Value (Detail) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013		Dec. 31, 2012
Financial assets:
Cash	$ 545		$ 197
Interest bearing deposits with banks	403		1,371
Securities purchased under agreements to resell	3,275		2,160
Real estate secured:
Derivative financial assets	131		0
Financial liabilities:
Long-term debt carried at fair value	9,600		9,700
Long-term debt not carried at fair value	27,555		28,426
Level 1
Financial assets:
Cash	545		197
Interest bearing deposits with banks	0		0
Securities purchased under agreements to resell	0		0
Securities			80
Real estate secured:
Total real estate secured	0	[1]	0	[1]
Receivables held for sale	0		0
Due from affiliates	0		0
Derivative financial assets	0		0
Financial liabilities:
Due to affiliates carried at fair value	0		0
Due to affiliates not carried at fair value	0		0
Long-term debt carried at fair value	0		0
Long-term debt not carried at fair value	0		0
Derivative financial liabilities	0		0
Level 1 | First Mortgage [Member]
Real estate secured:
Total real estate secured	0	[1]	0	[1]
Level 1 | Second Mortgage [Member]
Real estate secured:
Total real estate secured	0	[1]	0	[1]
Level 2
Financial assets:
Cash	0		0
Interest bearing deposits with banks	403		1,371
Securities purchased under agreements to resell	3,275		2,160
Securities			0
Real estate secured:
Total real estate secured	0	[1]	0	[1]
Receivables held for sale	0		0
Due from affiliates	0		105
Derivative financial assets	131		0
Financial liabilities:
Due to affiliates carried at fair value	511		514
Due to affiliates not carried at fair value	8,678		8,654
Long-term debt carried at fair value	9,573		9,725
Long-term debt not carried at fair value	15,959		16,537
Derivative financial liabilities	1		22
Level 2 | First Mortgage [Member]
Real estate secured:
Total real estate secured	0	[1]	0	[1]
Level 2 | Second Mortgage [Member]
Real estate secured:
Total real estate secured	0	[1]	0	[1]
Level 3
Financial assets:
Cash	0		0
Interest bearing deposits with banks	0		0
Securities purchased under agreements to resell	0		0
Securities			0
Real estate secured:
Total real estate secured	21,030	[1]	20,699	[1]
Receivables held for sale	0		0
Due from affiliates	0		0
Derivative financial assets	0		0
Financial liabilities:
Due to affiliates carried at fair value	0		0
Due to affiliates not carried at fair value	0		0
Long-term debt carried at fair value	0		0
Long-term debt not carried at fair value	2,591		2,635
Derivative financial liabilities	0		0
Level 3 | First Mortgage [Member]
Real estate secured:
Total real estate secured	19,776	[1]	19,586	[1]
Level 3 | Second Mortgage [Member]
Real estate secured:
Total real estate secured	1,254	[1]	1,113	[1]
Carrying Value
Financial assets:
Cash	545		197
Interest bearing deposits with banks	403		1,371
Securities purchased under agreements to resell	3,275		2,160
Securities			80
Real estate secured:
Total real estate secured	28,544	[1]	29,284	[1]
Receivables held for sale	6,354		6,203
Due from affiliates	0		105
Derivative financial assets	131		0
Financial liabilities:
Due to affiliates carried at fair value	511		514
Due to affiliates not carried at fair value	8,574		8,575
Long-term debt carried at fair value	9,573		9,725
Long-term debt not carried at fair value	17,982		18,701
Derivative financial liabilities	1		22
Carrying Value | First Mortgage [Member]
Real estate secured:
Total real estate secured	25,606	[1]	26,218	[1]
Carrying Value | Second Mortgage [Member]
Real estate secured:
Total real estate secured	2,938	[1]	3,066	[1]
Fair Value
Financial assets:
Cash	545		197
Interest bearing deposits with banks	403		1,371
Securities purchased under agreements to resell	3,275		2,160
Securities			80
Real estate secured:
Total real estate secured	21,030	[1]	20,699	[1]
Receivables held for sale	6,354		6,203
Due from affiliates	0		105
Derivative financial assets	131		0
Financial liabilities:
Due to affiliates carried at fair value	511		514
Due to affiliates not carried at fair value	8,678		8,654
Long-term debt carried at fair value	9,573		9,725
Long-term debt not carried at fair value	18,550		19,172
Derivative financial liabilities	1		22
Fair Value | First Mortgage [Member]
Real estate secured:
Total real estate secured	19,776	[1]	19,586	[1]
Fair Value | Second Mortgage [Member]
Real estate secured:
Total real estate secured	$ 1,254	[1]	$ 1,113	[1]

[1] The carrying amount of consumer receivables presented in the table above reflects the amortized cost of the receivable, including any accrued interest, less credit loss reserves as well as any charge-offs recorded in accordance with our existing charge-off policies.