Equity (Components of Accumulated Other Comprehensive Income (Loss)) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period	$ 11,058	$ 6,202	$ 5,104	$ 11,397
OCI before reclassifications	(174)	(1,618)	9,288	(8,713)
Deferred income tax expense (benefit)	(85)	580	(3,143)	2,555
OCI before reclassifications, net of income tax	10,799	5,164	11,249	5,239
Amounts reclassified from AOCI	302	(75)	(13)	(203)
Deferred income tax expense (benefit)	(109)	11	(10)	64
Amounts reclassified from AOCI, net of income tax	193	(64)	(23)	(139)
Balance, end of period	10,992	5,100	10,992	5,100
Unrealized Investment Gains (Losses), Net of Related Offsets [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period	13,909	9,709	8,183	13,590
OCI before reclassifications	(56)	(1,437)	9,126	(6,931)
Deferred income tax expense (benefit)	130	377	(2,851)	2,296
OCI before reclassifications, net of income tax	13,983	8,649	14,458	8,955
Amounts reclassified from AOCI	(214)	95	(563)	(374)
Deferred income tax expense (benefit)	62	(40)	176	123
Amounts reclassified from AOCI, net of income tax	(152)	55	(387)	(251)
Balance, end of period	13,831	8,704	13,831	8,704
Unrealized Gains (Losses) on Derivatives [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period	476	734	231	829
OCI before reclassifications	118	(287)	614	(660)
Deferred income tax expense (benefit)	(49)	103	(210)	221
OCI before reclassifications, net of income tax	545	550	635	390
Amounts reclassified from AOCI	471	(224)	337	10
Deferred income tax expense (benefit)	(158)	70	(114)	(4)
Amounts reclassified from AOCI, net of income tax	313	(154)	223	6
Balance, end of period	858	396	858	396
Foreign Currency Translation Adjustments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period	(1,739)	(1,825)	(1,659)	(533)
OCI before reclassifications	(264)	107	(486)	(1,123)
Deferred income tax expense (benefit)	(157)	100	(71)	38
OCI before reclassifications, net of income tax	(2,160)	(1,618)	(2,216)	(1,618)
Amounts reclassified from AOCI	0	0	77	0
Deferred income tax expense (benefit)	0	0	(27)	0
Amounts reclassified from AOCI, net of income tax	0	0	50	0
Balance, end of period	(2,160)	(1,618)	(2,160)	(1,618)
Defined Benefit Plans Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period	(1,588)	(2,416)	(1,651)	(2,489)
OCI before reclassifications	28	(1)	34	1
Deferred income tax expense (benefit)	(9)	0	(11)	0
OCI before reclassifications, net of income tax	(1,569)	(2,417)	(1,628)	(2,488)
Amounts reclassified from AOCI	45	54	136	161
Deferred income tax expense (benefit)	(13)	(19)	(45)	(55)
Amounts reclassified from AOCI, net of income tax	32	35	91	106
Balance, end of period	(1,537)	(2,382)	(1,537)	(2,382)
MetLife Assurance Limited [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts reclassified from AOCI	0		(314)
Deferred income tax expense (benefit)	0		80
Amounts reclassified from AOCI, net of income tax	0		(234)
MetLife Assurance Limited [Member] | Unrealized Investment Gains (Losses), Net of Related Offsets [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts reclassified from AOCI	0		(320)
Deferred income tax expense (benefit)	0		80
Amounts reclassified from AOCI, net of income tax	0		(240)
MetLife Assurance Limited [Member] | Unrealized Gains (Losses) on Derivatives [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts reclassified from AOCI	0		0
Deferred income tax expense (benefit)	0		0
Amounts reclassified from AOCI, net of income tax	0		0
MetLife Assurance Limited [Member] | Foreign Currency Translation Adjustments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts reclassified from AOCI	0		6
Deferred income tax expense (benefit)	0		0
Amounts reclassified from AOCI, net of income tax	0		6
MetLife Assurance Limited [Member] | Defined Benefit Plans Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts reclassified from AOCI	0		0
Deferred income tax expense (benefit)	0		0
Amounts reclassified from AOCI, net of income tax	$ 0		$ 0