Deferred Policy Acquisition Costs, Value of Business Acquired and Other Policy-Related Intangibles (Estimated Future Amortization) (Details) $ in Millions	12 Months Ended
Dec. 31, 2016 USD ($)
Estimated future amortization expense allocated to other expenses for VOBA [Abstract]
VOBA 2017	$ 110
VOBA 2018	94
VOBA 2019	80
VOBA 2020	60
VOBA 2021	52
Value of Distribution Agreements and Customer Relationships Acquired [Abstract]
VODA and VOCRA 2017	15
VODA and VOCRA 2018	14
VODA and VOCRA 2019	13
VODA and VOCRA 2020	12
VODA and VOCRA 2021	$ 10

No definition available.

Name:	us-gaap_ExpectedAmortizationExpenseOfEndingPresentValueOfFutureInsuranceProfitsNetOfInterestAccruedAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Expected amortization expense in the fifth year after the balance sheet date of the present value of the future profits of long-duration contracts acquired in a purchase of an insurance enterprise.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 20
-Section S99
-Paragraph 2
-Subparagraph (3)
-URI http://asc.fasb.org/extlink&oid=27015749&loc=d3e569990-122904

+ Details

Name:	us-gaap_ExpectedAmortizationExpenseOfEndingPresentValueOfFutureInsuranceProfitsYearFive
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Expected amortization expense in the fourth year after the balance sheet date of the present value of the future profits of long-duration contracts acquired in a purchase of an insurance enterprise.

+ References

+ Details

Name:	us-gaap_ExpectedAmortizationExpenseOfEndingPresentValueOfFutureInsuranceProfitsYearFour
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Expected amortization expense in the first year after the balance sheet date of the present value of the future profits of long-duration contracts acquired in a purchase of an insurance enterprise.

+ References

+ Details

Name:	us-gaap_ExpectedAmortizationExpenseOfEndingPresentValueOfFutureInsuranceProfitsYearOne
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Expected amortization expense in the third year after the balance sheet date of the present value of the future profits of long-duration contracts acquired in a purchase of an insurance enterprise.

+ References

+ Details

Name:	us-gaap_ExpectedAmortizationExpenseOfEndingPresentValueOfFutureInsuranceProfitsYearThree
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Expected amortization expense in the second year after the balance sheet date of the present value of the future profits of long-duration contracts acquired in a purchase of an insurance enterprise.

+ References

+ Details

Name:	us-gaap_ExpectedAmortizationExpenseOfEndingPresentValueOfFutureInsuranceProfitsYearTwo
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of amortization expense for assets, excluding financial assets and goodwill, lacking physical substance with a finite life expected to be recognized during the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 50
-Paragraph 2
-Subparagraph (a)(3)
-URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275

+ Details

Name:	us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of amortization expense for assets, excluding financial assets and goodwill, lacking physical substance with a finite life expected to be recognized during the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

+ Details

Name:	us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of amortization expense for assets, excluding financial assets and goodwill, lacking physical substance with a finite life expected to be recognized during the fourth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

+ Details

Name:	us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of amortization expense for assets, excluding financial assets and goodwill, lacking physical substance with a finite life expected to be recognized during the third fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

+ Details

Name:	us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of amortization expense for assets, excluding financial assets and goodwill, lacking physical substance with a finite life expected to be recognized during the second fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

+ Details

Name:	us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- References

No definition available.

+ Details

Name:	us-gaap_FiniteLivedIntangibleAssetsFutureAmortizationExpenseAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration