Equity (Components of Accumulated Other Comprehensive Income (Loss)) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance beginning of period	$ 1,628	$ 2,426	$ 980
OCI before reclassifications	(283)	(1,306)	2,487
Deferred income tax benefit (expense)	86	483	(788)
AOCI before reclassifications, net of income tax	1,431	1,603	2,679
Amounts reclassified from AOCI	(44)	40	(26)
Deferred income tax benefit (expense)	15	(15)	7
Amounts reclassified from AOCI, net of income tax	(29)	25	(19)
Balance end of period	1,402	1,628	2,426
Unrealized Investment Gains (Losses), Net of Related Offsets
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance beginning of period	1,415	2,250	916
OCI before reclassifications	(348)	(1,370)	2,301
Deferred income tax benefit (expense)	110	506	(707)
AOCI before reclassifications, net of income tax	1,177	1,386	2,510
Amounts reclassified from AOCI	(1)	46	(28)
Deferred income tax benefit (expense)	0	(17)	8
Amounts reclassified from AOCI, net of income tax	(1)	29	(20)
Balance end of period	1,176	1,415	2,250
Unrealized Gains (Losses) on Derivatives
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance beginning of period	239	183	25
OCI before reclassifications	68	92	242
Deferred income tax benefit (expense)	(24)	(32)	(85)
AOCI before reclassifications, net of income tax	283	243	182
Amounts reclassified from AOCI	(43)	(6)	2
Deferred income tax benefit (expense)	15	2	(1)
Amounts reclassified from AOCI, net of income tax	(28)	(4)	1
Balance end of period	255	239	183
Foreign Currency Translation Adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance beginning of period	(26)	(7)	39
OCI before reclassifications	(3)	(28)	(56)
Deferred income tax benefit (expense)	0	9	4
AOCI before reclassifications, net of income tax	(29)	(26)	(13)
Amounts reclassified from AOCI	0	0	0
Deferred income tax benefit (expense)	0	0	0
Amounts reclassified from AOCI, net of income tax	0	0	0
Balance end of period	$ (29)	$ (26)	(7)
MetLife Assurance Limited
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts reclassified from AOCI			(314)
Deferred income tax benefit (expense)			80
Amounts reclassified from AOCI, net of income tax			(234)
MetLife Assurance Limited | Unrealized Investment Gains (Losses), Net of Related Offsets
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts reclassified from AOCI			(320)
Deferred income tax benefit (expense)			80
Amounts reclassified from AOCI, net of income tax			(240)
MetLife Assurance Limited | Unrealized Gains (Losses) on Derivatives
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts reclassified from AOCI			0
Deferred income tax benefit (expense)			0
Amounts reclassified from AOCI, net of income tax			0
MetLife Assurance Limited | Foreign Currency Translation Adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts reclassified from AOCI			6
Deferred income tax benefit (expense)			0
Amounts reclassified from AOCI, net of income tax			$ 6