Investments (Credit Losses Recognized In Earnings Related To OTTI Losses Recognized In Accumulated Other Comprehensive Income (Loss)) (Detail) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Other than temporary impairment credit lossesfor available for sale securities rollforward [Abstract]
Beginning Balance		$ 16	$ 175	$ 197
Additions For Credit Loss Impairments Recognized In The Current Period On Securities Not Previous Impaired		0	15	0
Additions For Credit Loss Impairments Recognized In The Current Period On Securities Previously Impaired		10	1	0
Reductions For Credit Loss Impairments Previously Recognized On Securities Sold During The Period		0	(174)	(16)
Reductions For Credit Loss Impairments Previously Recognized On Securities Impaired To Fair Value During The Period	[1]	0	0	0
Reductions For Increases In Cash Flows Expected To Be Collected Over The Remaining Life Of The Security		0	(1)	(6)
Ending Balance		$ 26	$ 16	$ 175

[1] Represents circumstances where the Company determined in the current period that it intends to sell the security or it is more likely than not that it will be required to sell the security before recovery of the security's amortized cost.