Investments (Amortized Cost And Fair Value Of Available-For-Sale and Held-To-Maturity Investment Portfolios) (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012
Available For Sale Securities [Abstract]
Amortized cost	$ 6,824		$ 6,122
Gross unrealized gains	97		251
Gross unrealized losses	(229)		(152)
Total available-for-sale, fair value	6,692		6,221
Other-than-temporary impairments	(10)	[1]	(20)	[1]
Held To Maturity Securities [Abstract]
Amortized cost	2,801		2,829
Gross unrealized gains	31		2
Gross unrealized losses	(181)		(157)
Total held-to- maturity, fair value	2,651		2,674
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			38
Gross unrealized gains			3
Gross unrealized losses			0
Total available-for-sale, fair value			41
Other-than-temporary impairments			0	[1]
Corporate Obligations [Member] | Variable Interest Entity Primary Beneficiary [Member]
Available For Sale Securities [Abstract]
Amortized cost			177
Gross unrealized gains			9
Gross unrealized losses			(6)
Total available-for-sale, fair value			180
Other-than-temporary impairments			0	[1]
Held To Maturity Securities [Abstract]
Amortized cost	2,801		2,829
Gross unrealized gains	31		2
Gross unrealized losses	(181)		(157)
Total held-to- maturity, fair value	2,651		2,674
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			92
Gross unrealized gains			0
Gross unrealized losses			(10)
Total available-for-sale, fair value			82
Other-than-temporary impairments			0	[1]
Collateralized Debt Obligations [Member] | Variable Interest Entity Primary Beneficiary [Member]
Available For Sale Securities [Abstract]
Amortized cost			97
Gross unrealized gains			0
Gross unrealized losses			(8)
Total available-for-sale, fair value			89
Other-than-temporary impairments			0	[1]
Other Asset-Backed [Member] | Variable Interest Entity Primary Beneficiary [Member]
Available For Sale Securities [Abstract]
Amortized cost			23
Gross unrealized gains			0
Gross unrealized losses			0
Total available-for-sale, fair value			23
Other-than-temporary impairments			0	[1]
Money Market Securities [Member]
Available For Sale Securities [Abstract]
Amortized cost	781		580
Gross unrealized gains	0		0
Gross unrealized losses	0		0
Total available-for-sale, fair value	781		580
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	136		210
Gross unrealized gains	0		0
Gross unrealized losses	0		0
Total available-for-sale, fair value	136		210
Other-than-temporary impairments	0	[1]	0	[1]
Perpetual Debt And Equity Securities [Member]
Available For Sale Securities [Abstract]
Amortized cost	10		22
Gross unrealized gains	1		1
Gross unrealized losses	0		0
Total available-for-sale, fair value	11		23
Other-than-temporary impairments	0	[1]	0	[1]
Fixed Maturities [Member]
Available For Sale Securities [Abstract]
Amortized cost	5,897		4,883
Gross unrealized gains	96		238
Gross unrealized losses	(229)		(128)
Total available-for-sale, fair value	5,764		4,993
Other-than-temporary impairments	(10)	[1]	(20)	[1]
Fixed Maturities [Member] | Variable Interest Entity Primary Beneficiary [Member]
Held To Maturity Securities [Abstract]
Amortized cost	2,801
Total held-to- maturity, fair value	2,651
Fixed Maturities [Member] | U S Treasury And Government [Member]
Available For Sale Securities [Abstract]
Amortized cost	528		819
Gross unrealized gains	16		40
Gross unrealized losses	(9)		(1)
Total available-for-sale, fair value	535		858
Other-than-temporary impairments	0	[1]	0	[1]
Fixed Maturities [Member] | US States And Political Subdivisions [Member]
Available For Sale Securities [Abstract]
Amortized cost	1,831		1,446
Gross unrealized gains	22		97
Gross unrealized losses	(73)		(12)
Total available-for-sale, fair value	1,780		1,531
Other-than-temporary impairments	0	[1]	0	[1]
Fixed Maturities [Member] | Foreign Governments [Member]
Available For Sale Securities [Abstract]
Amortized cost	184		183
Gross unrealized gains	5		13
Gross unrealized losses	0		0
Total available-for-sale, fair value	189		196
Other-than-temporary impairments	0	[1]	0	[1]
Fixed Maturities [Member] | Corporate Obligations [Member]
Available For Sale Securities [Abstract]
Amortized cost	1,682		1,058
Gross unrealized gains	24		54
Gross unrealized losses	(38)		(20)
Total available-for-sale, fair value	1,668		1,092
Other-than-temporary impairments	0	[1]	5	[1]
Fixed Maturities [Member] | Residential Mortgage-Backed Agency [Member]
Available For Sale Securities [Abstract]
Amortized cost	1,167		939
Gross unrealized gains	10		19
Gross unrealized losses	(31)		(1)
Total available-for-sale, fair value	1,146		957
Other-than-temporary impairments	0	[1]	0	[1]
Fixed Maturities [Member] | Residential Mortgage-Backed Non-Agency [Member]
Available For Sale Securities [Abstract]
Amortized cost	79		86
Gross unrealized gains	13		11
Gross unrealized losses	(5)		(8)
Total available-for-sale, fair value	87		89
Other-than-temporary impairments	4	[1]	0	[1]
Fixed Maturities [Member] | Commercial Mortgage-Backed [Member]
Available For Sale Securities [Abstract]
Amortized cost	34		46
Gross unrealized gains	1		0
Gross unrealized losses	(1)		(4)
Total available-for-sale, fair value	34		42
Other-than-temporary impairments	0	[1]	0	[1]
Fixed Maturities [Member] | Collateralized Debt Obligations [Member]
Available For Sale Securities [Abstract]
Amortized cost	205		161
Gross unrealized gains	3		1
Gross unrealized losses	(57)		(71)
Total available-for-sale, fair value	151		91
Other-than-temporary impairments	(14)	[1]	(25)	[1]
Fixed Maturities [Member] | Other Asset-Backed [Member]
Available For Sale Securities [Abstract]
Amortized cost	187		145
Gross unrealized gains	2		3
Gross unrealized losses	(15)		(11)
Total available-for-sale, fair value	174		137
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.