Equity (Components of Accumulated Other Comprehensive Income (Loss)) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period	$ 8,215	$ 10,580	$ 5,104	$ 11,397
OCI before reclassifications	4,506	(6,262)	9,462	(7,095)
Deferred income tax expense (benefit)	(1,333)	1,953	(3,058)	1,975
OCI before reclassifications, net of income tax	11,388	6,271	11,508	6,277
Amounts reclassified from AOCI	(133)	(84)	(315)	(128)
Deferred income tax expense (benefit)	37	15	99	53
Amounts reclassified from AOCI, net of income tax	(96)	(69)	(216)	(75)
Balance, end of period	11,058	6,202	11,058	6,202
Unrealized Investment Gains (Losses), Net of Related Offsets [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period	11,276	13,332	8,183	13,590
OCI before reclassifications	4,330	(5,320)	9,182	(5,494)
Deferred income tax expense (benefit)	(1,336)	1,844	(2,981)	1,919
OCI before reclassifications, net of income tax	14,270	9,856	14,384	10,015
Amounts reclassified from AOCI	(176)	(189)	(349)	(469)
Deferred income tax expense (benefit)	55	42	114	163
Amounts reclassified from AOCI, net of income tax	(121)	(147)	(235)	(306)
Balance, end of period	13,909	9,709	13,909	9,709
Unrealized Gains (Losses) on Derivatives [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period	404	905	231	829
OCI before reclassifications	175	(311)	496	(373)
Deferred income tax expense (benefit)	(48)	96	(161)	118
OCI before reclassifications, net of income tax	531	690	566	574
Amounts reclassified from AOCI	(80)	53	(134)	234
Deferred income tax expense (benefit)	25	(9)	44	(74)
Amounts reclassified from AOCI, net of income tax	(55)	44	(90)	160
Balance, end of period	476	734	476	734
Foreign Currency Translation Adjustments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period	(1,843)	(1,205)	(1,659)	(533)
OCI before reclassifications	(5)	(633)	(222)	(1,230)
Deferred income tax expense (benefit)	53	13	86	(62)
OCI before reclassifications, net of income tax	(1,795)	(1,825)	(1,795)	(1,825)
Amounts reclassified from AOCI	77	0	77	0
Deferred income tax expense (benefit)	(27)	0	(27)	0
Amounts reclassified from AOCI, net of income tax	50	0	50	0
Balance, end of period	(1,739)	(1,825)	(1,739)	(1,825)
Defined Benefit Plans Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period	(1,622)	(2,452)	(1,651)	(2,489)
OCI before reclassifications	6	2	6	2
Deferred income tax expense (benefit)	(2)	0	(2)	0
OCI before reclassifications, net of income tax	(1,618)	(2,450)	(1,647)	(2,487)
Amounts reclassified from AOCI	46	52	91	107
Deferred income tax expense (benefit)	(16)	(18)	(32)	(36)
Amounts reclassified from AOCI, net of income tax	30	34	59	71
Balance, end of period	(1,588)	(2,416)	(1,588)	(2,416)
MetLife Assurance Limited [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amounts reclassified from AOCI	(314)		(314)
Deferred income tax expense (benefit)	80		80
Amounts reclassified from AOCI, net of income tax	(234)		(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	(320)		(320)
Deferred income tax expense (benefit)	80		80
Amounts reclassified from AOCI, net of income tax	(240)		(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	6		6
Deferred income tax expense (benefit)	0		0
Amounts reclassified from AOCI, net of income tax	6		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