Commitments, Contingencies, And Guarantees (Net Realized Gains (Losses) Of Derivative Instrument Activity In Consolidated Statement Of Operations) (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013		Mar. 31, 2012
Commitments Contingencies And Guarantees [Line Items]
Net realized gains (losses)	$ 96		$ 234
Foreign Exchange Future [Member]
Commitments Contingencies And Guarantees [Line Items]
Net realized gains (losses)	5		(8)
All Other Futures Contracts And Options [Member]
Commitments Contingencies And Guarantees [Line Items]
Net realized gains (losses)	7		26
Convertibles and Bonds with Warrants Attached [Member]
Commitments Contingencies And Guarantees [Line Items]
Net realized gains (losses)	6		24
Investment And Embedded Derivative Instruments [Member]
Commitments Contingencies And Guarantees [Line Items]
Net realized gains (losses)	18		42
Guaranteed Living Benefits [Member]
Commitments Contingencies And Guarantees [Line Items]
Net realized gains (losses)	328	[1]	428	[1]
Single-Stock Future [Member]
Commitments Contingencies And Guarantees [Line Items]
Net realized gains (losses)	(237)	[2]	(213)	[2]
Options On Equity Market Indices [Member]
Commitments Contingencies And Guarantees [Line Items]
Net realized gains (losses)	(13)	[2]	(18)	[2]
Credit Default Swap [Member]
Commitments Contingencies And Guarantees [Line Items]
Net realized gains (losses)	0		(5)
Guaranteed Living Benefit And Other Derivative Instruments [Member]
Commitments Contingencies And Guarantees [Line Items]
Net realized gains (losses)	$ 78		$ 192

[1] Excludes foreign exchange gains (losses) related to GLB.

[2] Related to GMDB and GLB blocks of business.