Commitments, Contingencies, And Guarantees (Narrative) (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2013	Dec. 31, 2012
Commitments and Contingencies Disclosure [Abstract]
Carrying value of limited partnerships and partially-owned investment companies included in other investments	$ 1,796	$ 1,796
Funding commitments relating to limited partnerships and partially-owned investment companies	1,144	1,144
Derivative asset subject to a master netting agreement	63	63	35
Repurchase obligations	1,401	1,401	1,401
Securities lending payable	1,665	1,665	1,795
Securities lending collateral	1,662	1,662	1,791
Reductions to the amount of unrecognized tax benefits	5	5
Unrecognized tax benefits	$ 22	$ 22