Rollforward of Credit Losses Recognized in Earnings Related to Securities (Detail) (USD $) In Millions	6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010
Schedule of Available-for-sale Securities [Line Items]
Beginning balance	$ 20	$ 22
Additions/reductions	2	0	[1]
Increases in expected cash flows recognized over the remaining life of the securities	(1)
Ending balance	$ 21	$ 22

[1] During the six months ended June 30, 2010, the Company recognized $2 million of OTTI through earnings on debt securities in which no portion of the OTTI loss was included in OCI at any time during the period. OTTI related to these securities are excluded from this amount.