Fair Value (Financial Instruments Carried at Other Than Fair Value) (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Assets
Policy loans	$ 1,213	$ 1,216
Other Limited Partnership Interests	2,049	1,848
Other Investments	2,310	2,961
Liabilities
Policyholder account balances	35,757	36,976
Long-term Debt	2,939	3,350
Other Liabilities	6,298	6,547
Separate account liabilities	90,066	86,114
Mortgage Loan Commitments [Member]
Commitments [Abstract]
Commitments to fund bank credit facilities, bridge loans and private corporate bond investments	271	181
Commitments to Fund Bank Credit Facilities and Private Corporate Bond Investments [Member]
Commitments [Abstract]
Commitments to fund bank credit facilities, bridge loans and private corporate bond investments	104	144
Estimate of Fair Value, Fair Value Disclosure [Member]
Assets
Mortgage loans, net	6,738	7,009
Policy loans	1,287	1,311
Real estate joint ventures	103	101
Other Limited Partnership Interests	103	103
Other Investments	500	548
Premiums, reinsurance and other receivables	6,738	7,000
Liabilities
Policyholder account balances	24,049	24,520
Long-term Debt	1,037	1,076
Other Liabilities	672	237
Separate account liabilities	1,354	1,296
Estimate of Fair Value, Fair Value Disclosure [Member] | Mortgage Loan Commitments [Member]
Commitments [Abstract]
Commitments to fund bank credit facilities, bridge loans and private corporate bond investments	(9)	1
Estimate of Fair Value, Fair Value Disclosure [Member] | Commitments to Fund Bank Credit Facilities and Private Corporate Bond Investments [Member]
Commitments [Abstract]
Commitments to fund bank credit facilities, bridge loans and private corporate bond investments	(2)	6
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 1 [Member]
Assets
Mortgage loans, net	0	0
Policy loans	0	0
Real estate joint ventures	0	0
Other Limited Partnership Interests	0	0
Other Investments	0	0
Premiums, reinsurance and other receivables	0	0
Liabilities
Policyholder account balances	0	0
Long-term Debt	0	0
Other Liabilities	0	0
Separate account liabilities	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 1 [Member] | Mortgage Loan Commitments [Member]
Commitments [Abstract]
Commitments to fund bank credit facilities, bridge loans and private corporate bond investments	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 1 [Member] | Commitments to Fund Bank Credit Facilities and Private Corporate Bond Investments [Member]
Commitments [Abstract]
Commitments to fund bank credit facilities, bridge loans and private corporate bond investments	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 2 [Member]
Assets
Mortgage loans, net	0	0
Policy loans	867	861
Real estate joint ventures	0	0
Other Limited Partnership Interests	0	0
Other Investments	500	548
Premiums, reinsurance and other receivables	59	86
Liabilities
Policyholder account balances	0	0
Long-term Debt	1,037	1,076
Other Liabilities	513	81
Separate account liabilities	1,354	1,296
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 2 [Member] | Mortgage Loan Commitments [Member]
Commitments [Abstract]
Commitments to fund bank credit facilities, bridge loans and private corporate bond investments	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 2 [Member] | Commitments to Fund Bank Credit Facilities and Private Corporate Bond Investments [Member]
Commitments [Abstract]
Commitments to fund bank credit facilities, bridge loans and private corporate bond investments	(2)	6
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 3 [Member]
Assets
Mortgage loans, net	6,738	7,009
Policy loans	420	450
Real estate joint ventures	103	101
Other Limited Partnership Interests	103	103
Other Investments	0	0
Premiums, reinsurance and other receivables	6,679	6,914
Liabilities
Policyholder account balances	24,049	24,520
Long-term Debt	0	0
Other Liabilities	159	156
Separate account liabilities	0	0
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 3 [Member] | Mortgage Loan Commitments [Member]
Commitments [Abstract]
Commitments to fund bank credit facilities, bridge loans and private corporate bond investments	(9)	1
Estimate of Fair Value, Fair Value Disclosure [Member] | Level 3 [Member] | Commitments to Fund Bank Credit Facilities and Private Corporate Bond Investments [Member]
Commitments [Abstract]
Commitments to fund bank credit facilities, bridge loans and private corporate bond investments	0	0
Carrying Value [Member]
Assets
Mortgage loans, net	6,341	6,491
Policy loans	1,213	1,216
Real estate joint ventures	56	59
Other Limited Partnership Interests	86	94
Other Investments	432	432
Premiums, reinsurance and other receivables	6,026	6,015
Liabilities
Policyholder account balances	22,429	22,613
Long-term Debt	791	791
Other Liabilities	672	237
Separate account liabilities	1,354	1,296
Carrying Value [Member] | Mortgage Loan Commitments [Member]
Commitments [Abstract]
Commitments to fund bank credit facilities, bridge loans and private corporate bond investments	0	0
Carrying Value [Member] | Commitments to Fund Bank Credit Facilities and Private Corporate Bond Investments [Member]
Commitments [Abstract]
Commitments to fund bank credit facilities, bridge loans and private corporate bond investments	$ 0	$ 0