Variable Interest Entities (Narrative) (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Variable Interest Entity [Line Items]
Carrying amounts of assets	$ 5,600,000,000	$ 8,300,000,000
Carrying amounts of liabilities	5,300,000,000	7,300,000,000
Number of variable interest entities consolidated	0	0
Net realized gains (losses) related to deconsolidation	1,000,000	0	271,000,000
Net realized gains (losses) related to the initial consolidation			$ (16,000,000)