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Fair Value (Table of reconciliation for assets and liabilities measured at fair value on a recurring basis using significant unobservable inputs) (Details) (USD $) In Millions, unless otherwise specified | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2013 | Jun. 30, 2012 | Jun. 30, 2013 | Jun. 30, 2012
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |
Balance, Beginning, Assets | $ 1,600 | $ 1,851 | $ 1,393 | $ 1,751
Net realized investment gains (losses) and net change in unrealized appreciation (depreciation) included in net income (loss) | (1) | 28 | (5) | 39
Net change in unrealized appreciation (depreciation) included in other comprehensive income (loss) | (1) | 7 | 8 | 14
Purchases | 143 | 378 | 608 | 789
Sales | (153) | (180) | (318) | (363)
Settlements | (50) | (164) | (115) | (259)
Transfers into Level 3 | 30 | 9 | 56 | 42
Transfers out of Level 3 | (115) | (56) | (174) | (140)
Balance, Ending, Assets | 1,453 | 1,873 | 1,453 | 1,873
Unrealized gains (losses) on Level 3 assets and liabilities held at balance sheet date recognized in net income (loss) | (10) | 2 | (26) |
Corporate and other bonds [Member] |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |
Balance, Beginning, Assets | 302 | 486 | 219 | 482
Net realized investment gains (losses) and net change in unrealized appreciation (depreciation) included in net income (loss) | 1 | 3 | 1 | 6
Net change in unrealized appreciation (depreciation) included in other comprehensive income (loss) | (3) | 2 | (1) | 6
Purchases | 13 | 68 | 123 | 147
Sales | (73) | (27) | (90) | (113)
Settlements | (6) | (13) | (26) | (32)
Transfers into Level 3 |  | 9 | 26 | 42
Transfers out of Level 3 | (32) | (40) | (50) | (50)
Balance, Ending, Assets | 202 | 488 | 202 | 488
Unrealized gains (losses) on Level 3 assets and liabilities held at balance sheet date recognized in net income (loss) | (1) |  | (2) |
States, municipalities and political subdivisions [Member] |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |
Balance, Beginning, Assets | 129 | 173 | 96 | 171
Net realized investment gains (losses) and net change in unrealized appreciation (depreciation) included in net income (loss) |  |  | (3) |
Net change in unrealized appreciation (depreciation) included in other comprehensive income (loss) | 4 | 1 | 4 | 3
Purchases | 37 |  | 122 |
Sales | (32) |  | (79) |
Settlements | (3) | (85) | (5) | (85)
Transfers into Level 3 | 5 |  | 5 |
Transfers out of Level 3 |  |  |  |
Balance, Ending, Assets | 140 | 89 | 140 | 89
Unrealized gains (losses) on Level 3 assets and liabilities held at balance sheet date recognized in net income (loss) |  |  |  |
Residential mortgage-backed [Member] |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |
Balance, Beginning, Assets | 450 | 447 | 413 | 452
Net realized investment gains (losses) and net change in unrealized appreciation (depreciation) included in net income (loss) | (1) | 1 | 2 | 2
Net change in unrealized appreciation (depreciation) included in other comprehensive income (loss) | (1) | (18) | (1) | (22)
Purchases | 50 | 22 | 111 | 60
Sales | (10) |  | (10) |
Settlements | (21) | (9) | (32) | (16)
Transfers into Level 3 | 4 |  | 4 |
Transfers out of Level 3 | (43) |  | (59) | (33)
Balance, Ending, Assets | 428 | 443 | 428 | 443
Unrealized gains (losses) on Level 3 assets and liabilities held at balance sheet date recognized in net income (loss) | (2) |  | (2) |
Commercial mortgage-backed [Member] |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |
Balance, Beginning, Assets | 177 | 105 | 129 | 59
Net realized investment gains (losses) and net change in unrealized appreciation (depreciation) included in net income (loss) |  | 2 | 1 | 2
Net change in unrealized appreciation (depreciation) included in other comprehensive income (loss) | 4 | 4 | 9 | 8
Purchases | 5 | 87 | 78 | 129
Sales |  | (12) |  | (12)
Settlements | (2) | (4) | (9) | (4)
Transfers into Level 3 | 21 |  | 21 |
Transfers out of Level 3 | (40) | (16) | (64) | (16)
Balance, Ending, Assets | 165 | 166 | 165 | 166
Unrealized gains (losses) on Level 3 assets and liabilities held at balance sheet date recognized in net income (loss) |  |  |  |
Other asset-backed [Member] |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |
Balance, Beginning, Assets | 396 | 384 | 368 | 343
Net realized investment gains (losses) and net change in unrealized appreciation (depreciation) included in net income (loss) |  | 2 | 3 | 6
Net change in unrealized appreciation (depreciation) included in other comprehensive income (loss) | (3) | (1) | (2) | 3
Purchases | 38 | 182 | 174 | 358
Sales | (33) | (99) | (132) | (176)
Settlements | (11) | (34) | (24) | (59)
Transfers into Level 3 |  |  |  |
Transfers out of Level 3 |  |  |  | (41)
Balance, Ending, Assets | 387 | 434 | 387 | 434
Unrealized gains (losses) on Level 3 assets and liabilities held at balance sheet date recognized in net income (loss) | (1) |  | (1) |
Total asset-backed [Member] |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |
Balance, Beginning, Assets | 1,023 | 936 | 910 | 854
Net realized investment gains (losses) and net change in unrealized appreciation (depreciation) included in net income (loss) | (1) | 5 | 6 | 10
Net change in unrealized appreciation (depreciation) included in other comprehensive income (loss) |  | (15) | 6 | (11)
Purchases | 93 | 291 | 363 | 547
Sales | (43) | (111) | (142) | (188)
Settlements | (34) | (47) | (65) | (79)
Transfers into Level 3 | 25 |  | 25 |
Transfers out of Level 3 | (83) | (16) | (123) | (90)
Balance, Ending, Assets | 980 | 1,043 | 980 | 1,043
Unrealized gains (losses) on Level 3 assets and liabilities held at balance sheet date recognized in net income (loss) | (3) |  | (3) |
Redeemable preferred stock [Member] |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |
Balance, Beginning, Assets | 26 | 53 | 26 |
Net realized investment gains (losses) and net change in unrealized appreciation (depreciation) included in net income (loss) |  |  |  |
Net change in unrealized appreciation (depreciation) included in other comprehensive income (loss) | (1) |  | (1) |
Purchases |  |  |  | 53
Sales |  | (26) |  | (26)
Settlements |  |  |  |
Transfers into Level 3 |  |  |  |
Transfers out of Level 3 |  |  |  |
Balance, Ending, Assets | 25 | 27 | 25 | 27
Unrealized gains (losses) on Level 3 assets and liabilities held at balance sheet date recognized in net income (loss) |  |  |  |
Fixed maturity securities [Member] |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |
Balance, Beginning, Assets | 1,480 | 1,648 | 1,251 | 1,507
Net realized investment gains (losses) and net change in unrealized appreciation (depreciation) included in net income (loss) |  | 8 | 4 | 16
Net change in unrealized appreciation (depreciation) included in other comprehensive income (loss) |  | (12) | 8 | (2)
Purchases | 143 | 359 | 608 | 747
Sales | (148) | (164) | (311) | (327)
Settlements | (43) | (145) | (96) | (196)
Transfers into Level 3 | 30 | 9 | 56 | 42
Transfers out of Level 3 | (115) | (56) | (173) | (140)
Balance, Ending, Assets | 1,347 | 1,647 | 1,347 | 1,647
Unrealized gains (losses) on Level 3 assets and liabilities held at balance sheet date recognized in net income (loss) | (4) |  | (5) |
Equity securities [Member] |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |
Balance, Beginning, Assets | 19 | 74 | 34 | 67
Net realized investment gains (losses) and net change in unrealized appreciation (depreciation) included in net income (loss) | (5) |  | (20) |
Net change in unrealized appreciation (depreciation) included in other comprehensive income (loss) | (1) | 19 |  | 16
Purchases |  | 15 |  | 26
Sales |  | (15) |  | (16)
Settlements |  |  |  |
Transfers into Level 3 |  |  |  |
Transfers out of Level 3 |  |  | (1) |
Balance, Ending, Assets | 13 | 93 | 13 | 93
Unrealized gains (losses) on Level 3 assets and liabilities held at balance sheet date recognized in net income (loss) | (5) | (1) | (20) | (3)
Other invested assets, including derivatives, net |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |
Balance, Beginning, Assets | (1) | 10 |  | 10
Net realized investment gains (losses) and net change in unrealized appreciation (depreciation) included in net income (loss) |  |  |  |
Net change in unrealized appreciation (depreciation) included in other comprehensive income (loss) |  |  |  |
Purchases |  |  |  |
Sales |  |  | (1) |
Settlements | 1 |  | 1 |
Transfers into Level 3 |  |  |  |
Transfers out of Level 3 |  |  |  |
Balance, Ending, Assets |  | 10 |  | 10
Unrealized gains (losses) on Level 3 assets and liabilities held at balance sheet date recognized in net income (loss) |  |  |  |
Short term investments [Member] |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |
Balance, Beginning, Assets | 5 |  | 6 | 27
Net realized investment gains (losses) and net change in unrealized appreciation (depreciation) included in net income (loss) |  |  |  |
Net change in unrealized appreciation (depreciation) included in other comprehensive income (loss) |  |  |  |
Purchases |  | 4 |  | 16
Sales | (5) |  | (6) |
Settlements |  |  |  | (39)
Transfers into Level 3 |  |  |  |
Transfers out of Level 3 |  |  |  |
Balance, Ending, Assets |  | 4 |  | 4
Unrealized gains (losses) on Level 3 assets and liabilities held at balance sheet date recognized in net income (loss) |  |  |  |
Life settlement contracts [Member] |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |
Balance, Beginning, Assets | 95 | 115 | 100 | 117
Net realized investment gains (losses) and net change in unrealized appreciation (depreciation) included in net income (loss) | 4 | 20 | 11 | 23
Net change in unrealized appreciation (depreciation) included in other comprehensive income (loss) |  |  |  |
Purchases |  |  |  |
Sales |  |  |  |
Settlements | (8) | (19) | (20) | (24)
Transfers into Level 3 |  |  |  |
Transfers out of Level 3 |  |  |  |
Balance, Ending, Assets | 91 | 116 | 91 | 116
Unrealized gains (losses) on Level 3 assets and liabilities held at balance sheet date recognized in net income (loss) | (1) | 3 | (1) | 3
Separate account business [Member] |  |  |  |
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward] |  |  |  |
Balance, Beginning, Assets | 2 | 4 | 2 | 23
Net realized investment gains (losses) and net change in unrealized appreciation (depreciation) included in net income (loss) |  |  |  |
Net change in unrealized appreciation (depreciation) included in other comprehensive income (loss) |  |  |  |
Purchases |  |  |  |
Sales |  | (1) |  | (20)
Settlements |  |  |  |
Transfers into Level 3 |  |  |  |
Transfers out of Level 3 |  |  |  |
Balance, Ending, Assets | 2 | 3 | 2 | 3
Unrealized gains (losses) on Level 3 assets and liabilities held at balance sheet date recognized in net income (loss) |  |  |  |

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- Definition Unrealized gains (losses) Recognized in Net Income on Level 3 Assets and Liabilities Held + References No definition available. + Details
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- Definition Amount of gain (loss) recognized in earnings, arising from assets measured at fair value on a recurring basis using unobservable inputs (level 3). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=7578670&loc=d3e19207-110258 + Details
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- Definition Amount of gain (loss) recognized in other comprehensive income, arising from assets measured at fair value on a recurring basis using unobservable inputs (level 3). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(1a) -URI http://asc.fasb.org/extlink&oid=7578670&loc=d3e19207-110258 + Details
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- Definition Purchases that have taken place during the period in relation to assets measured at fair value and categorized within Level 3 of the fair value hierarchy. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=7578670&loc=d3e19207-110258 + Details
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- Definition Sales that have taken place during the period in relation to assets measured at fair value and categorized within Level 3 of the fair value hierarchy. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=7578670&loc=d3e19207-110258 + Details
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- Definition Settlements that have taken place during the period in relation to assets measured at fair value and categorized within Level 3 of the fair value hierarchy. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=7578670&loc=d3e19207-110258 + Details
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- Definition Transfers into assets measured at fair value and categorized within Level 3 of the fair value hierarchy that have taken place during the period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(3) -URI http://asc.fasb.org/extlink&oid=7578670&loc=d3e19207-110258 + Details
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- Definition Transfers out of assets measured at fair value and categorized within Level 3 of the fair value hierarchy that have taken place during the period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c)(3) -URI http://asc.fasb.org/extlink&oid=7578670&loc=d3e19207-110258 + Details
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- Definition This element represents an asset measured at fair value using significant unobservable inputs (Level 3) which is required for reconciliation purposes of beginning and ending balances. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=7578670&loc=d3e19207-110258 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 157 -Paragraph 32 -Subparagraph c -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. + Details
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