Receivables - Receivables (Detail) (USD $) In Millions, unless otherwise specified	Sep. 30, 2013		Jun. 30, 2013	Dec. 31, 2012		Sep. 30, 2012	Jun. 30, 2012	Dec. 31, 2011
Real estate secured:
Total receivables	$ 27,844					$ 33,963
Real estate secured	27,844	[1],[2]		32,939	[1],[2]
Accrued finance income	904			952
Credit loss reserve for owned receivables	(3,697)		(4,098)	(4,607)		(4,429)	(4,608)	(5,952)
Total receivables, net	25,051			29,284
First Lien [Member]
Real estate secured:
Total receivables	24,682			29,301		30,143
Credit loss reserve for owned receivables	(3,133)		(3,463)	(3,867)		(3,724)	(3,858)	(4,089)
Second Lien [Member]
Real estate secured:
Total receivables	3,162			3,638		3,820
Credit loss reserve for owned receivables	$ (564)		$ (635)	$ (740)		$ (705)	$ (750)	$ (823)

[1] At September 30, 2013 and December 31, 2012, nonaccrual real estate secured receivables held for investment include $1,260 million and $2,096 million, respectively, of TDR Loans, some of which may also be carried at fair value of the collateral less cost to sell

[2] At September 30, 2013 and December 31, 2012, nonaccrual real estate secured receivables held for investment include $637 million and $1,748 million, respectively, of receivables that are carried at the lower of amortized cost or fair value of the collateral less cost to sell.