Policyholder Account Balances, Future Policy Benefits and Claims and Separate Account Liabilities Policyholder Account Balances, Future Policy Benefits and Claims and Separate Account Liabilities (Separate Account Liabilities) (Details 2) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Separate Accounts Disclosure [Abstract]
Variable annuity	$ 64,744	$ 74,965
VUL insurance	6,073	7,429
Other insurance	25	31
Threadneedle investment liabilities	4,463	5,063
Total	$ 75,305	$ 87,488