Accumulated Other Comprehensive Income (Loss) - Summary of Changes in Accumulated Other Comprehensive Income (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended			9 Months Ended
	Sep. 30, 2013		Sep. 30, 2012	Sep. 30, 2013		Sep. 30, 2012	Dec. 31, 2012
Unrealized gains (losses) on cash flow hedging instruments:
Balance at beginning of period	$ (152)		$ (444)	$ (358)		$ (494)
Net gains arising during period, net of tax of $17 million and $15 million for the three months ended, $56 million and $39 million for the nine month period ended	30		30	102		71
Reclassification adjustment for losses realized in net income, net of tax of $1 million and $2 million for the three months ended, and $75 million and $7 million for the nine month period ended	2	[1]	4	136	[1]	13
Total other comprehensive income for period	32		34	238		84
Balance at end of period	(120)		(410)	(120)		(410)
Unrealized gains (losses) on securities available-for-sale, not other-than temporarily impaired:
Balance at beginning of period	0		109	115		102
Reclassification of unrealized losses on other-than-temporary impaired debt securities, net of tax of $- million and $- million, respectively				0		1
Net unrealized holding gains (losses) arising during period, net of tax of $- million and $13 million for the three month period ended, and $- million and $8 million for the six month period ended	0		20	0		35
Reclassification adjustment for (gains) losses realized in net income, net of tax of $- million and $(3) million for the three month period ended, and $(62) million adn $(7) million for the nine month period ended	0	[2]	(5)	(115)	[2]	(14)
Total other comprehensive income (loss) for period	0		15	(115)		21
Balance at end of period	0		124	0		124
Unrealized gains (losses) on other-than-temporarily impaired debt securities available-for-sale:
Balance at beginning of period	0		0	1		0
Reclassification of unrealized gains on other-than-temporary impaired debt securities, net of tax of $- million and $- million, respectively				0		(1)
Other-than-temporary impairment on debt securities available-for-sale recognized in other comprehensive income, net of tax of $__ million and $- million for the three month period ending, $__ million and $- million for the nine month period ended	0		1	0		1
Reclassification adjustment for (gains) losses realized in net income, net of tax of $- million and $- million, for the three and $(1) million and $- million for the nine month period ended	0	[2]	(1)	(1)	[2]	0
Total other comprehensive income (loss) for period	0		0	(1)		1
Balance at end of period	0		0	0		0
Pension and postretirement benefit plan liability:
Balance at beginning and end of period	(25)		(10)	(26)		(11)
Change in unfunded pension and postretirement liability, net of tax of $- million and $- million, respectively				0		0
Reclassification adjustment for gains realized in net income, net of tax of $- million and $1 million, respectively				1	[3]	1
Total other comprehensive income (loss) for period	0		0	1		1
Balance at end of period	(25)		(10)	(25)		(10)
Foreign currency translation adjustments:
Balance at beginning of period	0		7	11		7
Translation gains (losses), net of tax of $- million and $1 million for the three month period ended, and $(1) million and $1 million for the nine month period ended	0		4	(5)		4
Reclassification adjustment for gains realized in net income, net of tax of $(9) million and $- million, respectively	0	[1]	0	(6)	[1]	0
Total other comprehensive income (loss) for period	0		4	(11)		4
Balance at end of period	0		11	0		11
Total accumulated other comprehensive loss at end of period	$ (145)		$ (285)	$ (145)		$ (285)	$ (257)

[1] See the tables below for the components of the amounts reclassified during the three and nine months ended September 30, 2013 into income and location in our consolidated statement of income (loss)

[2] The amounts reclassified during the three and nine months ended September 30, 2013 are included in income (loss) from discontinued operations in our consolidated statement of income (loss).

[3] The amounts reclassified during the three and nine months ended September 30, 2013 are included as a component of salaries and employee benefits in our consolidated statement of income (loss).