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Investments (Gross Unrealized Losses Related To Available-For-Sale And Held-To-Maturity Investments) (Detail) (USD $) In Millions, unless otherwise specified | Mar. 31, 2014 | Dec. 31, 2013
--- | --- | ---
Available For Sale Securities [Abstract] |  |
Less than 12 months, fair value | $ 2,457 | $ 2,978
Less than 12 months, unrealized losses | (76) | (128)
12 months or longer, fair value | 534 | 479
12 months or longer, unrealized losses | (91) | (101)
Total available-for-sale, fair value | 2,991 | 3,457
Total available-for-sale, unrealized losses | (167) | (229)
Held To Maturity Securities [Abstract] |  |
Less than 12 months, fair value | 0 | 0
Less than 12 months, unrealized losses | 0 | 0
12 months or longer, fair value | 420 | 1,244
12 months or longer, unrealized losses | (155) | (181)
Total held-to-maturity, fair value | 420 | 1,244
Total held-to-maturity, unrealized losses | (155) | (181)
Corporate Obligations [Member] | Variable Interest Entity Primary Beneficiary [Member] |  |
Available For Sale Securities [Abstract] |  |
Less than 12 months, fair value |  | 0
Less than 12 months, unrealized losses |  | 0
12 months or longer, fair value |  | 0
12 months or longer, unrealized losses |  | 0
Total available-for-sale, fair value |  | 0
Total available-for-sale, unrealized losses |  | 0
Held To Maturity Securities [Abstract] |  |
Less than 12 months, fair value | 0 | 0
Less than 12 months, unrealized losses | 0 | 0
12 months or longer, fair value | 420 | 1,244
12 months or longer, unrealized losses | (155) | (181)
Total held-to-maturity, fair value | 420 | 1,244
Total held-to-maturity, unrealized losses | (155) | (181)
Residential Mortgage Backed Non Agency [Member] | Variable Interest Entity Primary Beneficiary [Member] |  |
Available For Sale Securities [Abstract] |  |
Less than 12 months, fair value |  | 0
Less than 12 months, unrealized losses |  | 0
12 months or longer, fair value |  | 0
12 months or longer, unrealized losses |  | 0
Total available-for-sale, fair value |  | 0
Total available-for-sale, unrealized losses |  | 0
Collateralized Debt Obligations [Member] | Variable Interest Entity Primary Beneficiary [Member] |  |
Available For Sale Securities [Abstract] |  |
Less than 12 months, fair value |  | 0
Less than 12 months, unrealized losses |  | 0
12 months or longer, fair value |  | 0
12 months or longer, unrealized losses |  | 0
Total available-for-sale, fair value |  | 0
Total available-for-sale, unrealized losses |  | 0
Other Asset Backed [Member] | Variable Interest Entity Primary Beneficiary [Member] |  |
Available For Sale Securities [Abstract] |  |
Less than 12 months, fair value |  | 0
Less than 12 months, unrealized losses |  | 0
12 months or longer, fair value |  | 0
12 months or longer, unrealized losses |  | 0
Total available-for-sale, fair value |  | 0
Total available-for-sale, unrealized losses |  | 0
Perpetual Debt And Equity Securities [Member] |  |
Available For Sale Securities [Abstract] |  |
Less than 12 months, fair value | 2 | 5
Less than 12 months, unrealized losses | 0 | 0
12 months or longer, fair value | 0 | 0
12 months or longer, unrealized losses | 0 | 0
Total available-for-sale, fair value | 2 | 5
Total available-for-sale, unrealized losses | 0 | 0
Fixed Maturities [Member] |  |
Available For Sale Securities [Abstract] |  |
Less than 12 months, fair value | 2,455 | 2,973
Less than 12 months, unrealized losses | (76) | (128)
12 months or longer, fair value | 534 | 479
12 months or longer, unrealized losses | (91) | (101)
Total available-for-sale, fair value | 2,989 | 3,452
Total available-for-sale, unrealized losses | (167) | (229)
Fixed Maturities [Member] | U S Treasury And Government [Member] |  |
Available For Sale Securities [Abstract] |  |
Less than 12 months, fair value | 261 | 269
Less than 12 months, unrealized losses | (7) | (9)
12 months or longer, fair value | 1 | 1
12 months or longer, unrealized losses | 0 | 0
Total available-for-sale, fair value | 262 | 270
Total available-for-sale, unrealized losses | (7) | (9)
Fixed Maturities [Member] | US States And Political Subdivisions [Member] |  |
Available For Sale Securities [Abstract] |  |
Less than 12 months, fair value | 639 | 1,112
Less than 12 months, unrealized losses | (26) | (65)
12 months or longer, fair value | 54 | 49
12 months or longer, unrealized losses | (6) | (8)
Total available-for-sale, fair value | 693 | 1,161
Total available-for-sale, unrealized losses | (32) | (73)
Fixed Maturities [Member] | Foreign Government Debt [Member] |  |
Available For Sale Securities [Abstract] |  |
Less than 12 months, fair value | 110 | 36
Less than 12 months, unrealized losses | 0 | 0
12 months or longer, fair value | 0 | 0
12 months or longer, unrealized losses | 0 | 0
Total available-for-sale, fair value | 110 | 36
Total available-for-sale, unrealized losses | 0 | 0
Fixed Maturities [Member] | Corporate Obligations [Member] |  |
Available For Sale Securities [Abstract] |  |
Less than 12 months, fair value | 812 | 788
Less than 12 months, unrealized losses | (29) | (30)
12 months or longer, fair value | 85 | 82
12 months or longer, unrealized losses | (5) | (8)
Total available-for-sale, fair value | 897 | 870
Total available-for-sale, unrealized losses | (34) | (38)
Fixed Maturities [Member] | Residential Mortgage Backed Agency [Member] |  |
Available For Sale Securities [Abstract] |  |
Less than 12 months, fair value | 592 | 713
Less than 12 months, unrealized losses | (13) | (23)
12 months or longer, fair value | 193 | 144
12 months or longer, unrealized losses | (9) | (8)
Total available-for-sale, fair value | 785 | 857
Total available-for-sale, unrealized losses | (22) | (31)
Fixed Maturities [Member] | Residential Mortgage Backed Non Agency [Member] |  |
Available For Sale Securities [Abstract] |  |
Less than 12 months, fair value | 5 | 17
Less than 12 months, unrealized losses | 0 | 0
12 months or longer, fair value | 22 | 22
12 months or longer, unrealized losses | (4) | (5)
Total available-for-sale, fair value | 27 | 39
Total available-for-sale, unrealized losses | (4) | (5)
Fixed Maturities [Member] | Commercial Mortgage Backed Securities [Member] |  |
Available For Sale Securities [Abstract] |  |
Less than 12 months, fair value | 14 | 11
Less than 12 months, unrealized losses | (1) | (1)
12 months or longer, fair value | 2 | 0
12 months or longer, unrealized losses | 0 | 0
Total available-for-sale, fair value | 16 | 11
Total available-for-sale, unrealized losses | (1) | (1)
Fixed Maturities [Member] | Collateralized Debt Obligations [Member] |  |
Available For Sale Securities [Abstract] |  |
Less than 12 months, fair value | 2 | 6
Less than 12 months, unrealized losses | 0 | 0
12 months or longer, fair value | 127 | 124
12 months or longer, unrealized losses | (55) | (57)
Total available-for-sale, fair value | 129 | 130
Total available-for-sale, unrealized losses | (55) | (57)
Fixed Maturities [Member] | Other Asset Backed [Member] |  |
Available For Sale Securities [Abstract] |  |
Less than 12 months, fair value | 20 | 21
Less than 12 months, unrealized losses | 0 | 0
12 months or longer, fair value | 50 | 57
12 months or longer, unrealized losses | (12) | (15)
Total available-for-sale, fair value | 70 | 78
Total available-for-sale, unrealized losses | $ (12) | $ (15)

X
- Definition Amount of accumulated pre-tax unrealized loss on investments classified as available-for-sale that have been in a loss position fortwelve months or longer impacting investments. + References No definition available. + Details
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- Definition Amount of accumulated pre-tax unrealized losses before deducting pre-tax unrealized gains on investments in available-for-sale securities impacting investments. + References No definition available. + Details
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- Definition Amount of accumulated pre-tax unrealized loss on investments classified as available-for-sale that have been in a loss position for less than twelve months impacting investments. + References No definition available. + Details
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- Definition This item represents the aggregate fair value of investments in debt and equity securities in an unrealized loss position which are categorized neither as held-to-maturity nor trading securities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 6 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27290-111563 + Details
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