Investments (Amortized Cost And Fair Value Of Available-For-Sale and Held-To-Maturity Investment Portfolios) (Detail) (USD $) In Millions, unless otherwise specified	Jun. 30, 2014		Dec. 31, 2013
Available For Sale Securities [Abstract]
Amortized cost	$ 6,783		$ 6,824
Gross unrealized gains	167		97
Gross unrealized losses	(90)		(229)
Total available-for-sale, fair value	6,860		6,692
Other-than-temporary impairments	(4)	[1]	(10)	[1]
Held To Maturity Securities [Abstract]
Amortized cost	2,787		2,801
Gross unrealized gains	123		31
Gross unrealized losses	(130)		(181)
Total held-to- maturity, fair value	2,780		2,651
Other-Than-Temporary Impairments	0	[1]	0	[1]
US States And Political Subdivisions [Member] | Variable Interest Entity Primary Beneficiary [Member]
Available For Sale Securities [Abstract]
Amortized cost			0
Gross unrealized gains			0
Gross unrealized losses			0
Total available-for-sale, fair value			0
Other-than-temporary impairments			0	[1]
Corporate Obligations [Member] | Variable Interest Entity Primary Beneficiary [Member]
Available For Sale Securities [Abstract]
Amortized cost			0
Gross unrealized gains			0
Gross unrealized losses			0
Total available-for-sale, fair value			0
Other-than-temporary impairments			0	[1]
Held To Maturity Securities [Abstract]
Amortized cost	2,787		2,801
Gross unrealized gains	123		31
Gross unrealized losses	(130)		(181)
Total held-to- maturity, fair value	2,780		2,651
Other-Than-Temporary Impairments	0	[1]	0	[1]
Residential Mortgage-Backed Non-Agency [Member] | Variable Interest Entity Primary Beneficiary [Member]
Available For Sale Securities [Abstract]
Amortized cost			0
Gross unrealized gains			0
Gross unrealized losses			0
Total available-for-sale, fair value			0
Other-than-temporary impairments			0	[1]
Collateralized Debt Obligations [Member] | Variable Interest Entity Primary Beneficiary [Member]
Available For Sale Securities [Abstract]
Amortized cost			0
Gross unrealized gains			0
Gross unrealized losses			0
Total available-for-sale, fair value			0
Other-than-temporary impairments			0	[1]
Other Asset-Backed [Member] | Variable Interest Entity Primary Beneficiary [Member]
Available For Sale Securities [Abstract]
Amortized cost			0
Gross unrealized gains			0
Gross unrealized losses			0
Total available-for-sale, fair value			0
Other-than-temporary impairments			0	[1]
Money Market Securities [Member]
Available For Sale Securities [Abstract]
Amortized cost	385		781
Gross unrealized gains	0		0
Gross unrealized losses	0		0
Total available-for-sale, fair value	385		781
Other-than-temporary impairments	0	[1]	0	[1]
Money Market Securities [Member] | Variable Interest Entity Primary Beneficiary [Member]
Available For Sale Securities [Abstract]
Amortized cost	0		136
Gross unrealized gains	0		0
Gross unrealized losses	0		0
Total available-for-sale, fair value	0		136
Other-than-temporary impairments	0	[1]	0	[1]
Perpetual Debt And Equity Securities [Member]
Available For Sale Securities [Abstract]
Amortized cost	11		10
Gross unrealized gains	1		1
Gross unrealized losses	0		0
Total available-for-sale, fair value	12		11
Other-than-temporary impairments	0	[1]	0	[1]
Fixed Maturities [Member]
Available For Sale Securities [Abstract]
Amortized cost	6,387		5,897
Gross unrealized gains	166		96
Gross unrealized losses	(90)		(229)
Total available-for-sale, fair value	6,463		5,764
Other-than-temporary impairments	(4)	[1]	(10)	[1]
Fixed Maturities [Member] | Variable Interest Entity Primary Beneficiary [Member]
Held To Maturity Securities [Abstract]
Amortized cost	2,787
Total held-to- maturity, fair value	2,780
Fixed Maturities [Member] | U S Treasury And Government [Member]
Available For Sale Securities [Abstract]
Amortized cost	556		528
Gross unrealized gains	29		16
Gross unrealized losses	(4)		(9)
Total available-for-sale, fair value	581		535
Other-than-temporary impairments	0	[1]	0	[1]
Fixed Maturities [Member] | US States And Political Subdivisions [Member]
Available For Sale Securities [Abstract]
Amortized cost	1,687		1,831
Gross unrealized gains	67		22
Gross unrealized losses	(16)		(73)
Total available-for-sale, fair value	1,738		1,780
Other-than-temporary impairments	0	[1]	0	[1]
Fixed Maturities [Member] | Foreign Governments [Member]
Available For Sale Securities [Abstract]
Amortized cost	308		184
Gross unrealized gains	6		5
Gross unrealized losses	(1)		0
Total available-for-sale, fair value	313		189
Other-than-temporary impairments	0	[1]	0	[1]
Fixed Maturities [Member] | Corporate Obligations [Member]
Available For Sale Securities [Abstract]
Amortized cost	2,235		1,682
Gross unrealized gains	40		24
Gross unrealized losses	(21)		(38)
Total available-for-sale, fair value	2,254		1,668
Other-than-temporary impairments	0	[1]	0	[1]
Fixed Maturities [Member] | Residential Mortgage-Backed Agency [Member]
Available For Sale Securities [Abstract]
Amortized cost	1,157		1,167
Gross unrealized gains	16		10
Gross unrealized losses	(12)		(31)
Total available-for-sale, fair value	1,161		1,146
Other-than-temporary impairments	0	[1]	0	[1]
Fixed Maturities [Member] | Residential Mortgage-Backed Non-Agency [Member]
Available For Sale Securities [Abstract]
Amortized cost	57		79
Gross unrealized gains	3		13
Gross unrealized losses	(4)		(5)
Total available-for-sale, fair value	56		87
Other-than-temporary impairments	(4)	[1]	4	[1]
Fixed Maturities [Member] | Commercial Mortgage-Backed [Member]
Available For Sale Securities [Abstract]
Amortized cost	28		34
Gross unrealized gains	1		1
Gross unrealized losses	0		(1)
Total available-for-sale, fair value	29		34
Other-than-temporary impairments	0	[1]	0	[1]
Fixed Maturities [Member] | Collateralized Debt Obligations [Member]
Available For Sale Securities [Abstract]
Amortized cost	123		205
Gross unrealized gains	0		3
Gross unrealized losses	(23)		(57)
Total available-for-sale, fair value	100		151
Other-than-temporary impairments	0	[1]	(14)	[1]
Fixed Maturities [Member] | Other Asset-Backed [Member]
Available For Sale Securities [Abstract]
Amortized cost	236		187
Gross unrealized gains	4		2
Gross unrealized losses	(9)		(15)
Total available-for-sale, fair value	231		174
Other-than-temporary impairments	$ 0	[1]	$ 0	[1]

[1] Represents unrealized gains or losses on other than temporarily impaired securities recognized in AOCI, which includes the non-credit component of impairments, as well as all subsequent changes in fair value of such impaired securities reported in AOCI.