Schedule V Valuation and Qualifying Accounts (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Allowance for doubtful accounts and other
Movement in Valuation allowance and reserves
Balance January 1,	$ 137	$ 134	$ 131
Increase (decrease) in Costs and Expenses	42	39	44
Write-offs/ Payments/ Other	(47)	(36)	(41)
Balance December 31,	132	137	134
Allowance for uncollectible reinsurance
Movement in Valuation allowance and reserves
Balance January 1,	165	266	271
Increase (decrease) in Costs and Expenses	4	3	12
Write-offs/ Payments/ Other	(65)	(104)	(17)
Balance December 31,	104	165	266
Valuation allowance on mortgage loans
Movement in Valuation allowance and reserves
Balance January 1,	0	4	3
Increase (decrease) in Costs and Expenses	1	0	3
Write-offs/ Payments/ Other	0	(4)	(2)
Balance December 31,	1	0	4
Valuation allowance for deferred taxes
Movement in Valuation allowance and reserves
Balance January 1,	0	79	181
Increase (decrease) in Costs and Expenses	0	(79)	(102)
Write-offs/ Payments/ Other	0	0	0
Balance December 31,	$ 0	$ 0	$ 79

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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- Definition

Total of allowances and reserves, the valuation and qualifying accounts that are either netted against the cost of an asset (in order to value it at its carrying value) or that reflect a liability established to represent expected future costs.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section S99
-Paragraph 4
-Subparagraph (SX 210.12-09)
-URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e24092-122690

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- Definition

Amount of increase in the allowances and reserves, which consist of the valuation and qualifying accounts that are either netted against the cost of an asset or that reflect a liability established to represent expected future costs, from charges to costs and expenses.

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