Fair Value (Financial Instruments Carried at Other Than Fair Value) (Details) - USD ($) $ in Millions	Jun. 30, 2015	Dec. 31, 2014
Assets
Policy loans	$ 11,575	$ 11,618
Liabilities
Collateral financing arrangements	4,164	4,196
Junior subordinated debt securities	3,193	3,193
Separate account liabilities	319,477	316,994
Estimated Fair Value
Assets
Mortgage loans	66,024	62,554
Policy loans	13,732	13,934
Real estate joint ventures	123	139
Other limited partnership interests	764	906
Other invested assets	525	562
Premiums, reinsurance and other receivables	4,977	3,157
Other assets	331	243
Liabilities
Policyholder account balances	133,064	139,359
Long-term debt	18,093	18,357
Collateral financing arrangements	3,939	3,961
Junior subordinated debt securities	4,106	4,173
Other liabilities	7,024	2,546
Separate account liabilities	118,341	116,665
Estimated Fair Value | Level 1
Assets
Mortgage loans	0	0
Policy loans	0	0
Real estate joint ventures	0	0
Other limited partnership interests	0	0
Other invested assets	161	172
Premiums, reinsurance and other receivables	0	0
Other assets	0	0
Liabilities
Policyholder account balances	0	0
Long-term debt	0	0
Collateral financing arrangements	0	0
Junior subordinated debt securities	0	0
Other liabilities	0	0
Separate account liabilities	0	0
Estimated Fair Value | Level 2
Assets
Mortgage loans	0	0
Policy loans	1,661	1,647
Real estate joint ventures	0	0
Other limited partnership interests	0	0
Other invested assets	33	70
Premiums, reinsurance and other receivables	2,613	713
Other assets	268	175
Liabilities
Policyholder account balances	0	0
Long-term debt	18,093	18,357
Collateral financing arrangements	0	0
Junior subordinated debt securities	4,106	4,173
Other liabilities	5,716	1,223
Separate account liabilities	118,341	116,665
Estimated Fair Value | Level 3
Assets
Mortgage loans	66,024	62,554
Policy loans	12,071	12,287
Real estate joint ventures	123	139
Other limited partnership interests	764	906
Other invested assets	331	320
Premiums, reinsurance and other receivables	2,364	2,444
Other assets	63	68
Liabilities
Policyholder account balances	133,064	139,359
Long-term debt	0	0
Collateral financing arrangements	3,939	3,961
Junior subordinated debt securities	0	0
Other liabilities	1,308	1,323
Separate account liabilities	0	0
Carrying Value
Assets
Mortgage loans	63,399	59,530
Policy loans	11,575	11,618
Real estate joint ventures	47	67
Other limited partnership interests	603	704
Other invested assets	525	562
Premiums, reinsurance and other receivables	4,933	3,070
Other assets	334	251
Liabilities
Policyholder account balances	128,707	134,219
Long-term debt	16,631	16,128
Collateral financing arrangements	4,164	4,196
Junior subordinated debt securities	3,193	3,193
Other liabilities	7,023	2,544
Separate account liabilities	$ 118,341	$ 116,665