Deferred Policy Acquisition Costs and Value of Business Acquired Level 4 (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Jun. 01, 2018	Dec. 31, 2017
Movement Analysis of Deferred Policy Acquisition Costs [Roll Forward]
Balance, beginning of period	$ 0	$ 405
Amortization — DAC	0	(8)
Amortization — unlock charge, pre-tax	0	(3)
Adjustments to unrealized gains and losses on securities AFS and other	0	23
Balance, end of period	0	417
Movement in Present Value of Future Insurance Profits [Roll Forward]
Present Value of Future Insurance Profits, Net	741	0	$ 716	$ 805	$ 0
Present Value of Future Insurance Profits, Amortization Expense	41	0
Present Value of Future Insurance Profits, Amortization Expense, Assumption Change	2	0
Present Value of Future Insurance Profits, Unrealized Gain (Loss) on Investment	(18)	$ 0
Present Value of Future Insurance Profits, Amortization Expense, Next Five Years [Abstract]
Present Value of Future Insurance Profits, Amortization Expense, Year One	25
Present Value of Future Insurance Profits, Amortization Expense, Year Two	42
Present Value of Future Insurance Profits, Amortization Expense, Year Three	53
Present Value of Future Insurance Profits, Amortization Expense, Year Four	47
Present Value of Future Insurance Profits, Amortization Expense, Year Five	$ 43