SCHEDULE I - CONSOLIDATED SUMMARY OF INVESTMENTS - OTHER THAN INVESTMENTS IN RELATED PARTIES (Details) $ in Millions	Dec. 31, 2017 USD ($)
Summary of investments, other than investments in related parties [Line Items]
Cost	$ 105,671
Carrying Value	113,089
Trading securities [Member]
Summary of investments, other than investments in related parties [Line Items]
Cost	1,425
Fair Value	1,620
Carrying Value	1,620
Mortgage Loans On Real Estate [Member]
Summary of investments, other than investments in related parties [Line Items]
Cost	10,762
Fair Value	10,877
Carrying Value	10,762
Real estate [Member]
Summary of investments, other than investments in related parties [Line Items]
Cost	11
Carrying Value	11
Policy loans [Member]
Summary of investments, other than investments in related parties [Line Items]
Cost	2,399
Carrying Value	2,399
Derivative instruments [Member]
Summary of investments, other than investments in related parties [Line Items]
Cost	1,538	[1]
Fair Value	915	[1]
Carrying Value	915	[1]
Derivative Liabilities	338
Other investments [Member]
Summary of investments, other than investments in related parties [Line Items]
Cost	2,296
Fair Value	2,296
Carrying Value	2,296
Fixed maturity AFS securities [Member]
Summary of investments, other than investments in related parties [Line Items]
Cost	86,993	[2]
Fair Value	94,840	[2]
Carrying Value	94,840	[2]
Fixed maturity AFS securities [Member] | Mortgage-Backed And Asset-Backed Securities [Member]
Summary of investments, other than investments in related parties [Line Items]
Cost	5,623
Fair Value	5,847
Carrying Value	5,847
Fixed maturity AFS securities [Member] | Hybrid and redeemable preferred securities [Member]
Summary of investments, other than investments in related parties [Line Items]
Cost	575	[2]
Fair Value	640	[2]
Carrying Value	640	[2]
Fixed maturity AFS securities [Member] | Bonds [Member] | U.S. government and government agencies and authorities [Member]
Summary of investments, other than investments in related parties [Line Items]
Cost	527	[2]
Fair Value	567	[2]
Carrying Value	567	[2]
Fixed maturity AFS securities [Member] | Bonds [Member] | Foreign governments [Member]
Summary of investments, other than investments in related parties [Line Items]
Cost	395	[2]
Fair Value	451	[2]
Carrying Value	451	[2]
Fixed maturity AFS securities [Member] | Bonds [Member] | State and municipal bonds [Member]
Summary of investments, other than investments in related parties [Line Items]
Cost	4,172	[2]
Fair Value	5,119	[2]
Carrying Value	5,119	[2]
Fixed maturity AFS securities [Member] | Bonds [Member] | Public utilities [Member]
Summary of investments, other than investments in related parties [Line Items]
Cost	12,785	[2]
Fair Value	14,244	[2]
Carrying Value	14,244	[2]
Fixed maturity AFS securities [Member] | Bonds [Member] | All other corporate bonds [Member]
Summary of investments, other than investments in related parties [Line Items]
Cost	62,916	[2]
Fair Value	67,972	[2]
Carrying Value	67,972	[2]
Equity AFS securities [Member]
Summary of investments, other than investments in related parties [Line Items]
Cost	247	[2]
Fair Value	246	[2]
Carrying Value	246	[2]
Equity AFS securities [Member] | Nonredeemable preferred securities [Member]
Summary of investments, other than investments in related parties [Line Items]
Cost	19	[2]
Fair Value	25	[2]
Carrying Value	25	[2]
Equity AFS securities [Member] | Common Stock [Member] | Banks, trusts, and insurance companies [Member]
Summary of investments, other than investments in related parties [Line Items]
Cost	184	[2]
Fair Value	188	[2]
Carrying Value	188	[2]
Equity AFS securities [Member] | Common Stock [Member] | Industrial, miscellaneous and all other [Member]
Summary of investments, other than investments in related parties [Line Items]
Cost	44	[2]
Fair Value	33	[2]
Carrying Value	$ 33	[2]

[1] Derivative investment assets were offset by $338 million in derivative liabilities reflected in other liabilities on our Consolidated Balance Sheets.

[2] Investments deemed to have declines in value that are other-than-temporary are written down or reserved for to reduce the carrying value to their estimated realizable value.