Dispositions - Separation of Brighthouse - Agreements (Details) - USD ($) $ in Millions	10 Months Ended	12 Months Ended
	Oct. 31, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Related Party Transaction [Line Items]
Income Taxes Receivable		$ 0	$ 20
Net cash paid (received) for Income tax		1,530	672	$ 1,127
Other Assets		8,167	$ 7,058
Brighthouse Financial, Inc [Member]
Related Party Transaction [Line Items]
Income Taxes Receivable		1,400
Net cash paid (received) for Income tax	$ 729
Related Party Transaction, Due from (to) Related Party		(1,400)
Discontinued Operation, Tax separation agreement Expense		1,093
Decrease to current income tax recoverable		1,093
Other Assets		333
Impact of U.S. Tax Reform | Brighthouse Financial, Inc [Member]
Related Party Transaction [Line Items]
Other Assets		$ 222