Related Party Transactions (Effects of Affiliated Reinsurance on Balance Sheets) (Details) - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Assets:
Assets	$ 204,968	$ 212,045
Premiums, reinsurance and other receivables	12,815	12,918
Deferred policy acquisition costs and value of business acquired	5,385	5,623
Liabilities:
Liabilities	189,767	195,177
Future policy benefits	35,123	35,715
Policyholder account balances	38,650	37,069
Other Liabilities	4,654	4,419
Assumed
Assets:
Premiums, reinsurance and other receivables	19	34
Liabilities:
Policyholder account balances	289	436
Other policy-related balances	10	1,683
Other Liabilities	(38)	(8)
Ceded
Assets:
Premiums, reinsurance and other receivables	0	3,254
Liabilities:
Policyholder account balances	0	0
Other policy-related balances	0	0
Other Liabilities	$ 0	$ 401