Variable Interest Entities - Fair Value Hierarchy of Consolidated VIEs (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Trading securities
Investment funds	$ 2,460	$ 2,264
Recurring \| Variable Interest Entities \| Level 1
Available-for-sale securities
Equity securities	161
Trading securities
Fixed maturity securities	0	0
Equity securities	74	271
Investment funds	0	0
Cash and cash equivalents	14	6
Total assets not carried at fair value	249	277
Recurring \| Variable Interest Entities \| Level 2
Available-for-sale securities
Equity securities	0
Trading securities
Fixed maturity securities	0	669
Equity securities	0	0
Investment funds	0	0
Cash and cash equivalents	0	0
Total assets not carried at fair value	0	669
Recurring \| Variable Interest Entities \| Level 3
Available-for-sale securities
Equity securities	0
Trading securities
Fixed maturity securities	50	53
Equity securities	43	38
Investment funds	562	516
Cash and cash equivalents	0	0
Total assets not carried at fair value	655	607
Recurring \| Variable Interest Entities \| Fair Value
Available-for-sale securities
Equity securities	161
Trading securities
Fixed maturity securities	50	722
Equity securities	117	309
Investment funds	562	516
Cash and cash equivalents	14	6
Total assets not carried at fair value	$ 904	$ 1,553

Other investments including, but not limited to: partnership interests, credit funds, hedge funds, and private equity.

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- Definition

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

+ 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 (a)
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- Definition

Amount of equity securities categorized neither as held-to-maturity nor as trading.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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- Definition

Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=6506951

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- Definition

Amount of investments in debt securities classified as trading.

+ References

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- Definition

Fair value of investments in trading equity securities and other forms of trading securities that provide ownership interests.

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