Reserve for Future Policy Benefits and Separate Account Liabilities Level 4 Separate Accounts by Major Category of Investment (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
Net Amount at Risk by Product and Guarantee, General Account Value	$ 15,701
Schedule of Fair Value of Separate Accounts by Major Category of Investment, Fair Value	$ 30,239	$ 37,208
Invested in Fixed Income Securities	20.00%	15.00%
Invested in Equity Securities	80.00%	85.00%
Equity Securities [Member]
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
Schedule of Fair Value of Separate Accounts by Major Category of Investment, Fair Value	$ 28,953	$ 34,496
Cash and Cash Equivalents [Member]
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
Schedule of Fair Value of Separate Accounts by Major Category of Investment, Fair Value	1,286	2,712
Guaranteed Minimum Death Benefit [Member]
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
Net Amount at Risk by Product and Guarantee, General Account Value	3,387
Guaranteed Minimum Death Benefit [Member] | Deferred Annuitization [Member]
Schedule of Fair Value of Separate Accounts by Major Category of Investment [Line Items]
Net Amount at Risk by Product and Guarantee, General Account Value	$ 1,846	$ 1,900