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Reinsurance (Components of Reinsurance Receivables) (Details) - USD ($) $ in Millions | Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015 | Dec. 31, 2014
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Reinsurance receivables related to insurance reserves |  |  |  |
Ceded claim and claim adjustment expenses | $ 3,934 | $ 4,094 | $ 4,087 | $ 4,344
Ceded future policy benefits | 230 | 212 |  |
Reinsurance receivables related to paid losses | 126 | 147 |  |
Reinsurance receivables | 4,290 | 4,453 |  |
Allowance for uncollectible reinsurance | (29) | (37) |  |
Reinsurance receivables, net of allowance for uncollectible reinsurance | $ 4,261 | $ 4,416 |  |

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- Definition Ceded Claim And Claim Adjustment Expenses + References No definition available. + Details
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- Definition Ceded Future Policy Benefits + References No definition available. + Details
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- References No definition available. + Details
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- Definition Amount, after valuation allowance, recoverable under reinsurance contracts including premium paid under reinsurance contracts. Examples include, but are not limited to, settled and unsettled claims, incurred but not reported losses, loss adjustment expense, premium paid, policy benefits and policy reserves. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 20 -Section 50 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=6480758&loc=d3e6824-158387 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 310 -Section 45 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=6485522&loc=d3e21409-158489 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.(a),6) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 + Details
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- Definition Amount of valuation allowance for reinsurance recoverables. Examples include, but are not limited to, settled and unsettled claims, incurred but not reported losses, loss adjustment expense, premium paid, policy benefits and policy reserves. + References No definition available. + Details
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- Definition Amount before valuation allowance recoverable under reinsurance contracts. Examples include, but are not limited to, settled and unsettled claims, incurred but not reported losses, loss adjustment expense, premium paid, policy benefits and policy reserves. + References No definition available. + Details
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- Definition Amount before valuation allowance of reinsurance recoverables on paid losses. + References No definition available. + Details
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