Condensed Financial Information (Parent Company) (Investment in Subsidiaries - Narrative) (Details) - USD ($) $ in Millions		1 Months Ended	12 Months Ended
	Aug. 03, 2017	Feb. 29, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Condensed Financial Statements, Captions [Line Items]
Dividends Paid To Registrant's Parent Company By Affiliates	$ 1,800
Preferred Stock, Value, Issued			$ 0	$ 0
Common Stock, Value, Issued			12	12
Parent Company
Condensed Financial Statements, Captions [Line Items]
Non Cash Dividends From Subsidiaries			0	2,652	$ 0
Capital Contributions To Subsidiaries			339	1,733	667
Investment in subsidiaries			73,274	85,429
Preferred Stock, Value, Issued			0	0
Common Stock, Value, Issued			12	12
Returns of capital from subsidiaries			17,518	372	4,284
Capital contributions to subsidiaries			$ 15,655	$ 157	4,120
MetLife Insurance Company USA | Parent Company
Condensed Financial Statements, Captions [Line Items]
Capital Contributions To Subsidiaries		$ 1,500
Metlife Reinsurance Company of Vermont | Parent Company | Investments in Majority-owned Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Investment in subsidiaries					50	$ 350
MetLife Reinsurance Company of Delaware | Parent Company | Investments in Majority-owned Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Investment in subsidiaries					45	$ 95
MetLife Reinsurance Company Of South Carolina | Parent Company | Investments in Majority-owned Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Investment in subsidiaries					$ 25