Reinsurance (Effects of Reinsurance on Balance Sheet) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Assets
Premiums, reinsurance and other receivables	$ 23,439	$ 23,637
Deferred policy acquisition costs and value of business acquired	5,975	6,416	5,832
Total assets	29,414	30,053
Liabilities:
Future policy benefits	117,402	111,963
Policyholder account balances	95,902	92,498	94,716
Other policy-related balances	5,840	5,671
Other Liabilities	33,447	32,180
Total liabilities	252,591	242,312
Assumed Reinsurance [Member]
Assets
Premiums, reinsurance and other receivables	649	527
Deferred policy acquisition costs and value of business acquired	391	330
Total assets	1,040	857
Liabilities:
Future policy benefits	2,259	1,891
Policyholder account balances	301	252
Other policy-related balances	455	294
Other Liabilities	7,020	7,046
Total liabilities	10,035	9,483
Ceded Reinsurance [Member]
Assets
Premiums, reinsurance and other receivables	21,079	21,410
Deferred policy acquisition costs and value of business acquired	(418)	(481)
Total assets	20,661	20,929
Liabilities:
Future policy benefits	0	0
Policyholder account balances	0	0
Other policy-related balances	32	(39)
Other Liabilities	16,077	16,444
Total liabilities	16,109	16,405
Direct Reinsurance [Member]
Assets
Premiums, reinsurance and other receivables	1,711	1,700
Deferred policy acquisition costs and value of business acquired	6,002	6,567
Total assets	7,713	8,267
Liabilities:
Future policy benefits	115,143	110,072
Policyholder account balances	95,601	92,246
Other policy-related balances	5,353	5,416
Other Liabilities	10,350	8,690
Total liabilities	$ 226,447	$ 216,424