Related Party Transactions (Effects of Affiliated Reinsurance on Balance Sheets) (Details) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Assets:
Assets	$ 204,579	$ 212,045
Premiums, reinsurance and other receivables	13,024	12,918
Deferred policy acquisition costs and value of business acquired	5,343	5,623
Liabilities:
Liabilities	188,824	195,177
Future policy benefits	35,183	35,715
Policyholder account balances	37,629	37,069
Other Liabilities	4,589	4,419
Assumed
Assets:
Premiums, reinsurance and other receivables	19	34
Liabilities:
Policyholder account balances	321	436
Other policy-related balances	14	1,683
Other Liabilities	(45)	(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