Fair Value of Assets and Liabilities (Level 3 Assets and Liabilities) (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2017	Mar. 31, 2016
Assets
Balance at beginning of period	$ 514	$ 720
Total gains (losses) included in: Net income	5	(1)
Total gains (losses) included in: OCI	8	(2)
Transfers into Level 3	3	3
Transfers out of Level 3	(12)	(12)
Purchases	13	60
Sales	(1)	(16)
Issues	0	0
Settlements	(8)	(9)
Balance at end of period	522	743
Liabilities
Balance at beginning of period	(289)	(299)
Total gains (losses) included in: net income	3	(15)
Total gains (losses) included in: OCI	0	0
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Purchases	0	0
Sales	0	0
Issues	(1)	(1)
Settlements	2	2
Balance at end of period	(285)	(313)
Fixed income securities
Assets
Balance at beginning of period	439	666
Total gains (losses) included in: Net income	0	12
Total gains (losses) included in: OCI	8	(5)
Transfers into Level 3	3	3
Transfers out of Level 3	(12)	(12)
Purchases	13	55
Sales	0	(16)
Issues	0	0
Settlements	(8)	(9)
Balance at end of period	443	694
Municipal
Assets
Balance at beginning of period	59	78
Total gains (losses) included in: Net income	0	11
Total gains (losses) included in: OCI	1	(8)
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Purchases	0	0
Sales	0	(15)
Issues	0	0
Settlements	0	0
Balance at end of period	60	66
Corporate - public
Assets
Balance at beginning of period	47	44
Total gains (losses) included in: Net income	1	0
Total gains (losses) included in: OCI	0	1
Transfers into Level 3	0	1
Transfers out of Level 3	(10)	(7)
Purchases	0	0
Sales	0	0
Issues	0	0
Settlements	(2)	(1)
Balance at end of period	36	38
Corporate - privately placed
Assets
Balance at beginning of period	264	447
Total gains (losses) included in: Net income	0	1
Total gains (losses) included in: OCI	5	4
Transfers into Level 3	0	0
Transfers out of Level 3	0	(5)
Purchases	0	55
Sales	0	0
Issues	0	0
Settlements	(1)	(5)
Balance at end of period	268	497
ABS - CDO
Assets
Balance at beginning of period	27	53
Total gains (losses) included in: Net income	(1)	0
Total gains (losses) included in: OCI	2	(1)
Transfers into Level 3	3	2
Transfers out of Level 3	0	0
Purchases	5	0
Sales	0	(1)
Issues	0	0
Settlements	(4)	(3)
Balance at end of period	32	50
ABS - consumer and other
Assets
Balance at beginning of period	42	44
Total gains (losses) included in: Net income	0	0
Total gains (losses) included in: OCI	0	(1)
Transfers into Level 3	0	0
Transfers out of Level 3	(2)	0
Purchases	8	0
Sales	0	0
Issues	0	0
Settlements	(1)	0
Balance at end of period	47	43
Equity securities
Assets
Balance at beginning of period	76	60
Total gains (losses) included in: Net income	5	(12)
Total gains (losses) included in: OCI	0	3
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Purchases	0	5
Sales	(1)	0
Issues	0	0
Settlements	0	0
Balance at end of period	80	56
Free-standing derivatives, net
Assets
Balance at beginning of period	(2)	(7)
Total gains (losses) included in: Net income	1	(1)
Total gains (losses) included in: OCI	0	0
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Purchases	0	0
Sales	0	0
Issues	0	0
Settlements	0	0
Balance at end of period	(1)	(8)
Other assets
Assets
Balance at beginning of period	1	1
Total gains (losses) included in: Net income	(1)	0
Total gains (losses) included in: OCI	0	0
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Purchases	0	0
Sales	0	0
Issues	0	0
Settlements	0	0
Balance at end of period	0	1
Contractholder funds: Derivatives embedded in life and annuity contracts
Liabilities
Balance at beginning of period	(289)	(299)
Total gains (losses) included in: net income	3	(15)
Total gains (losses) included in: OCI	0	0
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Purchases	0	0
Sales	0	0
Issues	(1)	(1)
Settlements	2	2
Balance at end of period	$ (285)	$ (313)

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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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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Amount of transfers of financial instrument classified as a liability into level 3 of the fair value hierarchy.

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Amount of transfers of financial instrument classified as a liability out of level 3 of the fair value hierarchy.

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Amount of gain (loss) recognized in the income statement for financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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Amount of gain (loss) recognized in other comprehensive income (loss) for financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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Amount of issuances of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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Fair value of financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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