v3.8.0.1

Value of Business Acquired (Estimated Future Amortization, Net of Interest) (Details) $ in Millions | Dec. 31, 2017 USD ($)
--- | ---
Present Value of Future Insurance Profits [Abstract] |
Estimated future VOBA amortization - 2018 | $ 204
Estimated future VOBA amortization - 2019 | 182
Estimated future VOBA amortization - 2020 | 164
Estimated future VOBA amortization - 2021 | 152
Estimated future VOBA amortization - 2022 | $ 138

X
- References No definition available. + Details
Name: | us-gaap_PresentValueOfFutureInsuranceProfitsAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of amortization expense expected to be recognized during fifth fiscal year following latest fiscal year for present value of future profits of insurance contract acquired in business combination. + 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 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 805 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6918812&loc=d3e30762-158568 + Details
Name: | us-gaap_PresentValueOfFutureInsuranceProfitsAmortizationExpenseYearFive
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of amortization expense expected to be recognized during fourth fiscal year following latest fiscal year for present value of future profits of insurance contract acquired in business combination. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 805 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6918812&loc=d3e30762-158568 Reference 2: 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_PresentValueOfFutureInsuranceProfitsAmortizationExpenseYearFour
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of amortization expense expected to be recognized during next fiscal year following latest fiscal year for present value of future profits of insurance contract acquired in business combination. + 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 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 805 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6918812&loc=d3e30762-158568 + Details
Name: | us-gaap_PresentValueOfFutureInsuranceProfitsAmortizationExpenseYearOne
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of amortization expense expected to be recognized during third fiscal year following latest fiscal year for present value of future profits of insurance contract acquired in business combination. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 805 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6918812&loc=d3e30762-158568 Reference 2: 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_PresentValueOfFutureInsuranceProfitsAmortizationExpenseYearThree
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of amortization expense expected to be recognized during second fiscal year following latest fiscal year for present value of future profits of insurance contract acquired in business combination. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 805 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6918812&loc=d3e30762-158568 Reference 2: 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_PresentValueOfFutureInsuranceProfitsAmortizationExpenseYearTwo
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant