Fair Value Measurements - Assets and liabilities measured and carried at fair value in the financial statements (Details) - USD ($) $ in Millions		Sep. 30, 2016	Dec. 31, 2015
Assets:
Available for sale (AFS) fixed maturities		$ 35,394	$ 32,284
Trading fixed maturities		348	254
Assets of managed investment entities (“MIE”)		4,312	4,047
Variable annuity assets (separate accounts)	[1]	606	608
Total assets accounted for at fair value		42,760	39,155
Liabilities:
Liabilities of managed investment entities		4,067	3,781
Total liabilities accounted for at fair value		5,762	5,156
Annuity benefits accumulated
Liabilities:
Derivatives included in annuity benefits accumulated, long-term debt, and other liabilities		1,688	1,369
Derivatives in long-term debt
Liabilities:
Derivatives included in annuity benefits accumulated, long-term debt, and other liabilities		(6)	(2)
Other liabilities — derivatives
Liabilities:
Derivatives included in annuity benefits accumulated, long-term debt, and other liabilities		13	8
Fixed maturities
Assets:
Available for sale (AFS) fixed maturities		35,394	32,284
Trading fixed maturities		348	254
U.S. Government and government agencies
Assets:
Available for sale (AFS) fixed maturities		332	307
States, municipalities and political subdivisions
Assets:
Available for sale (AFS) fixed maturities		7,047	6,856
Foreign government
Assets:
Available for sale (AFS) fixed maturities		141	154
Residential MBS
Assets:
Available for sale (AFS) fixed maturities		3,816	3,529
Commercial MBS
Assets:
Available for sale (AFS) fixed maturities		1,849	2,187
Asset-backed securities (“ABS”)
Assets:
Available for sale (AFS) fixed maturities		5,889	4,934
Corporate and other
Assets:
Available for sale (AFS) fixed maturities		16,320	14,317
Equity securities
Assets:
Equity securities — AFS and trading		1,639	1,719
Other assets — derivatives
Assets:
Derivatives included in other investments and other assets		14	2
Level 1
Assets:
Assets of managed investment entities (“MIE”)		328	309
Variable annuity assets (separate accounts)	[1]	0	0
Total assets accounted for at fair value		1,881	1,834
Liabilities:
Liabilities of managed investment entities		310	289
Total liabilities accounted for at fair value		310	289
Level 1 | Annuity benefits accumulated
Liabilities:
Derivatives included in annuity benefits accumulated, long-term debt, and other liabilities		0	0
Level 1 | Derivatives in long-term debt
Liabilities:
Derivatives included in annuity benefits accumulated, long-term debt, and other liabilities		0	0
Level 1 | Other liabilities — derivatives
Liabilities:
Derivatives included in annuity benefits accumulated, long-term debt, and other liabilities		0	0
Level 1 | Fixed maturities
Assets:
Available for sale (AFS) fixed maturities		168	150
Trading fixed maturities		12	13
Level 1 | U.S. Government and government agencies
Assets:
Available for sale (AFS) fixed maturities		133	100
Level 1 | States, municipalities and political subdivisions
Assets:
Available for sale (AFS) fixed maturities		0	0
Level 1 | Foreign government
Assets:
Available for sale (AFS) fixed maturities		0	0
Level 1 | Residential MBS
Assets:
Available for sale (AFS) fixed maturities		0	0
Level 1 | Commercial MBS
Assets:
Available for sale (AFS) fixed maturities		0	0
Level 1 | Asset-backed securities (“ABS”)
Assets:
Available for sale (AFS) fixed maturities		0	0
Level 1 | Corporate and other
Assets:
Available for sale (AFS) fixed maturities		35	50
Level 1 | Equity securities
Assets:
Equity securities — AFS and trading		1,373	1,362
Level 1 | Other assets — derivatives
Assets:
Derivatives included in other investments and other assets		0	0
Level 2
Assets:
Assets of managed investment entities (“MIE”)		3,960	3,712
Variable annuity assets (separate accounts)	[1]	606	608
Total assets accounted for at fair value		39,162	35,685
Liabilities:
Liabilities of managed investment entities		3,734	3,468
Total liabilities accounted for at fair value		3,741	3,474
Level 2 | Annuity benefits accumulated
Liabilities:
Derivatives included in annuity benefits accumulated, long-term debt, and other liabilities		0	0
Level 2 | Derivatives in long-term debt
Liabilities:
Derivatives included in annuity benefits accumulated, long-term debt, and other liabilities		(6)	(2)
Level 2 | Other liabilities — derivatives
Liabilities:
Derivatives included in annuity benefits accumulated, long-term debt, and other liabilities		13	8
Level 2 | Fixed maturities
Assets:
Available for sale (AFS) fixed maturities		33,698	30,664
Trading fixed maturities		336	241
Level 2 | U.S. Government and government agencies
Assets:
Available for sale (AFS) fixed maturities		191	192
Level 2 | States, municipalities and political subdivisions
Assets:
Available for sale (AFS) fixed maturities		6,956	6,767
Level 2 | Foreign government
Assets:
Available for sale (AFS) fixed maturities		141	154
Level 2 | Residential MBS
Assets:
Available for sale (AFS) fixed maturities		3,597	3,305
Level 2 | Commercial MBS
Assets:
Available for sale (AFS) fixed maturities		1,815	2,148
Level 2 | Asset-backed securities (“ABS”)
Assets:
Available for sale (AFS) fixed maturities		5,422	4,464
Level 2 | Corporate and other
Assets:
Available for sale (AFS) fixed maturities		15,576	13,634
Level 2 | Equity securities
Assets:
Equity securities — AFS and trading		101	217
Level 2 | Other assets — derivatives
Assets:
Derivatives included in other investments and other assets		14	2
Level 3
Assets:
Assets of managed investment entities (“MIE”)		24	26
Variable annuity assets (separate accounts)	[1]	0	0
Total assets accounted for at fair value		1,717	1,636
Liabilities:
Liabilities of managed investment entities		23	24
Total liabilities accounted for at fair value		1,711	1,393
Level 3 | Annuity benefits accumulated
Liabilities:
Derivatives included in annuity benefits accumulated, long-term debt, and other liabilities		1,688	1,369
Level 3 | Derivatives in long-term debt
Liabilities:
Derivatives included in annuity benefits accumulated, long-term debt, and other liabilities		0	0
Level 3 | Other liabilities — derivatives
Liabilities:
Derivatives included in annuity benefits accumulated, long-term debt, and other liabilities		0	0
Level 3 | Fixed maturities
Assets:
Available for sale (AFS) fixed maturities		1,528	1,470
Trading fixed maturities		0	0
Level 3 | U.S. Government and government agencies
Assets:
Available for sale (AFS) fixed maturities		8	15
Level 3 | States, municipalities and political subdivisions
Assets:
Available for sale (AFS) fixed maturities		91	89
Level 3 | Foreign government
Assets:
Available for sale (AFS) fixed maturities		0	0
Level 3 | Residential MBS
Assets:
Available for sale (AFS) fixed maturities		219	224
Level 3 | Commercial MBS
Assets:
Available for sale (AFS) fixed maturities		34	39
Level 3 | Asset-backed securities (“ABS”)
Assets:
Available for sale (AFS) fixed maturities		467	470
Level 3 | Corporate and other
Assets:
Available for sale (AFS) fixed maturities		709	633
Level 3 | Equity securities
Assets:
Equity securities — AFS and trading		165	140
Level 3 | Other assets — derivatives
Assets:
Derivatives included in other investments and other assets		0	0
Equity index call options | Other investments — equity index call options
Assets:
Derivatives included in other investments and other assets		447	241
Equity index call options | Level 1 | Other investments — equity index call options
Assets:
Derivatives included in other investments and other assets		0	0
Equity index call options | Level 2 | Other investments — equity index call options
Assets:
Derivatives included in other investments and other assets		447	241
Equity index call options | Level 3 | Other investments — equity index call options
Assets:
Derivatives included in other investments and other assets		$ 0	$ 0

[1] Variable annuity liabilities equal the fair value of variable annuity assets.