Fair Value of Assets and Liabilities (Details) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014	Sep. 30, 2014
Assets
Fixed income securities:	$ 58,257	$ 62,440
Equity securities	4,236	4,104
Short-term investments	3,036	2,540
Other investments: Free-standing derivatives	1		$ 3
Separate account assets	3,677	4,396
Counterparty and cash collateral netting	$ (14)	$ (5)
% of total assets at fair value	0.00%	0.00%
Other liabilities:
Other liabilities: Free-standing derivatives	$ (9)		$ (9)
Counterparty and cash collateral netting	$ 5	$ 22
Counterparty and cash collateral netting as a percent of liabilities measured at fair value	(1.60%)	(6.10%)
U.S. government and agencies
Assets
Fixed income securities:	$ 3,760	$ 4,328
Municipal
Assets
Fixed income securities:	7,494	8,497
Corporate
Assets
Fixed income securities:	41,629	42,144
Foreign government
Assets
Fixed income securities:	1,085	1,645
Asset-backed securities (“ABS”)
Assets
Fixed income securities:	2,711	3,978
Residential mortgage-backed securities (“RMBS”)
Assets
Fixed income securities:	1,011	1,207
Commercial mortgage-backed securities (“CMBS”)
Assets
Fixed income securities:	542	615
Redeemable preferred stock
Assets
Fixed income securities:	25	26
Quoted prices in active markets for identical assets (Level 1)
Assets
Total assets at fair value	$ 10,806	12,117
% of total assets at fair value	15.60%
Other liabilities:
Total liabilities at fair value	$ (5)	$ (1)
Liabilities as a percent of liabilities measured at fair value	1.60%	0.30%
Significant other observable inputs (Level 2)
Assets
Total assets at fair value	$ 57,267	$ 59,985
% of total assets at fair value	82.70%	81.50%
Other liabilities:
Total liabilities at fair value	$ (14)	$ (50)
Liabilities as a percent of liabilities measured at fair value	4.40%	13.80%
Significant unobservable inputs (Level 3)
Assets
Total assets at fair value	$ 1,204	$ 1,487
% of total assets at fair value	1.70%	2.00%
Other liabilities:
Total liabilities at fair value	$ (304)	$ (332)
Liabilities as a percent of liabilities measured at fair value	95.60%	92.00%
Recurring
Assets
Other investments: Free-standing derivatives, Counterparty and cash collateral netting	$ (14)	$ (5)
Other liabilities:
Counterparty and cash collateral netting	5	22
Recurring | Quoted prices in active markets for identical assets (Level 1)
Assets
Fixed income securities:	2,851	3,240
Equity securities	3,925	3,787
Short-term investments	351	692
Other investments: Free-standing derivatives	0	0
Separate account assets	3,677	4,396
Other assets	2	2
Total assets at fair value	10,806	$ 12,117
% of total assets at fair value		16.50%
Other liabilities:
Other liabilities: Free-standing derivatives	(5)	$ (1)
Recurring | Quoted prices in active markets for identical assets (Level 1) | U.S. government and agencies
Assets
Fixed income securities:	2,851	3,240
Recurring | Quoted prices in active markets for identical assets (Level 1) | Municipal
Assets
Fixed income securities:	0	0
Recurring | Quoted prices in active markets for identical assets (Level 1) | Corporate
Assets
Fixed income securities:	0	0
Recurring | Quoted prices in active markets for identical assets (Level 1) | Foreign government
Assets
Fixed income securities:	0	0
Recurring | Quoted prices in active markets for identical assets (Level 1) | Asset-backed securities (“ABS”)
Assets
Fixed income securities:	0	0
Recurring | Quoted prices in active markets for identical assets (Level 1) | Residential mortgage-backed securities (“RMBS”)
Assets
Fixed income securities:	0	0
Recurring | Quoted prices in active markets for identical assets (Level 1) | Commercial mortgage-backed securities (“CMBS”)
Assets
Fixed income securities:	0	0
Recurring | Quoted prices in active markets for identical assets (Level 1) | Redeemable preferred stock
Assets
Fixed income securities:	0	0
Recurring | Significant other observable inputs (Level 2)
Assets
Fixed income securities:	54,410	57,813
Equity securities	170	234
Short-term investments	2,645	1,843
Other investments: Free-standing derivatives	42	95
Separate account assets	0	0
Other assets	0	0
Total assets at fair value	57,267	59,985
Other liabilities:
Other liabilities: Free-standing derivatives	(14)	(50)
Recurring | Significant other observable inputs (Level 2) | U.S. government and agencies
Assets
Fixed income securities:	904	1,082
Recurring | Significant other observable inputs (Level 2) | Municipal
Assets
Fixed income securities:	7,305	8,227
Recurring | Significant other observable inputs (Level 2) | Corporate
Assets
Fixed income securities:	41,029	41,253
Recurring | Significant other observable inputs (Level 2) | Foreign government
Assets
Fixed income securities:	1,085	1,645
Recurring | Significant other observable inputs (Level 2) | Asset-backed securities (“ABS”)
Assets
Fixed income securities:	2,529	3,782
Recurring | Significant other observable inputs (Level 2) | Residential mortgage-backed securities (“RMBS”)
Assets
Fixed income securities:	1,010	1,206
Recurring | Significant other observable inputs (Level 2) | Commercial mortgage-backed securities (“CMBS”)
Assets
Fixed income securities:	523	592
Recurring | Significant other observable inputs (Level 2) | Redeemable preferred stock
Assets
Fixed income securities:	25	26
Recurring | Significant unobservable inputs (Level 3)
Assets
Fixed income securities:	996	1,387
Equity securities	141	83
Short-term investments	40	5
Other investments: Free-standing derivatives	1	2
Separate account assets	0	0
Other assets	1	1
Total assets at fair value	1,179	1,478
Other liabilities:
Other liabilities: Free-standing derivatives	(9)	(9)
Recurring | Significant unobservable inputs (Level 3) | U.S. government and agencies
Assets
Fixed income securities:	5	6
Recurring | Significant unobservable inputs (Level 3) | Municipal
Assets
Fixed income securities:	189	270
Recurring | Significant unobservable inputs (Level 3) | Corporate
Assets
Fixed income securities:	600	891
Recurring | Significant unobservable inputs (Level 3) | Foreign government
Assets
Fixed income securities:	0	0
Recurring | Significant unobservable inputs (Level 3) | Asset-backed securities (“ABS”)
Assets
Fixed income securities:	182	196
Recurring | Significant unobservable inputs (Level 3) | Residential mortgage-backed securities (“RMBS”)
Assets
Fixed income securities:	1	1
Recurring | Significant unobservable inputs (Level 3) | Commercial mortgage-backed securities (“CMBS”)
Assets
Fixed income securities:	19	23
Recurring | Significant unobservable inputs (Level 3) | Redeemable preferred stock
Assets
Fixed income securities:	0	0
Non-recurring | Quoted prices in active markets for identical assets (Level 1)
Assets
Total assets at fair value	0	0
Non-recurring | Significant other observable inputs (Level 2)
Assets
Total assets at fair value	0	0
Non-recurring | Significant unobservable inputs (Level 3)
Assets
Total assets at fair value	25	9
Derivatives embedded in life and annuity contracts | Recurring | Quoted prices in active markets for identical assets (Level 1)
Contract holder funds:
Contractholder funds: Derivatives embedded in life and annuity contracts	0	0
Derivatives embedded in life and annuity contracts | Recurring | Significant other observable inputs (Level 2)
Contract holder funds:
Contractholder funds: Derivatives embedded in life and annuity contracts	0	0
Derivatives embedded in life and annuity contracts | Recurring | Significant unobservable inputs (Level 3)
Contract holder funds:
Contractholder funds: Derivatives embedded in life and annuity contracts	(295)	(323)
Estimate of Fair Value Measurement [Member]
Fair value of assets and liabilities measured on recurring and non-recurring basis
Limited partnership interests	8	3
Mortgage loans		6
Other Investments, Fair Value Disclosure	17
Assets
Total assets at fair value	$ 69,263	$ 73,584
% of total assets at fair value	100.00%	100.00%
Other liabilities:
Total liabilities at fair value	$ (318)	$ (361)
Liabilities as a percent of liabilities measured at fair value	100.00%	100.00%
Estimate of Fair Value Measurement [Member] | Recurring
Assets
Fixed income securities:	$ 58,257	$ 62,440
Equity securities	4,236	4,104
Short-term investments	3,036	2,540
Other investments: Free-standing derivatives	29	92
Separate account assets	3,677	4,396
Other assets	3	3
Total assets at fair value	69,238	73,575
Other liabilities:
Other liabilities: Free-standing derivatives	(23)	(38)
Estimate of Fair Value Measurement [Member] | Recurring | U.S. government and agencies
Assets
Fixed income securities:	3,760	4,328
Estimate of Fair Value Measurement [Member] | Recurring | Municipal
Assets
Fixed income securities:	7,494	8,497
Estimate of Fair Value Measurement [Member] | Recurring | Corporate
Assets
Fixed income securities:	41,629	42,144
Estimate of Fair Value Measurement [Member] | Recurring | Foreign government
Assets
Fixed income securities:	1,085	1,645
Estimate of Fair Value Measurement [Member] | Recurring | Asset-backed securities (“ABS”)
Assets
Fixed income securities:	2,711	3,978
Estimate of Fair Value Measurement [Member] | Recurring | Residential mortgage-backed securities (“RMBS”)
Assets
Fixed income securities:	1,011	1,207
Estimate of Fair Value Measurement [Member] | Recurring | Commercial mortgage-backed securities (“CMBS”)
Assets
Fixed income securities:	542	615
Estimate of Fair Value Measurement [Member] | Recurring | Redeemable preferred stock
Assets
Fixed income securities:	25	26
Estimate of Fair Value Measurement [Member] | Non-recurring
Assets
Total assets at fair value	25	9
Estimate of Fair Value Measurement [Member] | Derivatives embedded in life and annuity contracts | Recurring
Contract holder funds:
Contractholder funds: Derivatives embedded in life and annuity contracts	(295)	(323)
Fixed income securities - non-binding broker quotes
Assets
Total assets at fair value	676	1,030
Municipal - not rated by third party credit rating agencies
Assets
Total assets at fair value	$ 114	$ 169