Dispositions - Disposition of MetLife Afore (Details) - MetLife Afore $ in Millions	12 Months Ended
	Dec. 31, 2017 USD ($)
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Group, Including Discontinued Operation, Gross Profit (Loss)	$ (98)
Income (loss) on disposal of discontinued operations, net of income tax	(73)
Disposal Group, Including Discontinued Operation, Goodwill	16
Disposal Group, Including Discontinued Operation, Assets	3,900
Disposal Group, Including Discontinued Operation, Liabilities	3,700
Disposal Group, Including Discontinued Operation, Separate account assets	3,700
Disposal Group, Including Discontinued Operation, Separate account liabilities	$ 3,700