Investments (Changes in Net Unrealized Investment Gains Losses) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
Mar. 31, 2015
Changes In Net Unrealized Investment Gains Losses Included In Accumulated Other Comprehensive Loss [Abstract]
Balance, beginning of period	$ 16,235
Fixed maturity securities on which noncredit OTTI losses have been recognized	28
Unrealized investment gains (losses) during the period	3,534
Unrealized investment gains (losses) relating to [Abstract]
Future policy benefits	(856)
DAC and VOBA related to noncredit OTTI losses recognized in AOCI	3
DAC, VOBA and DSI	(116)
Policyholder dividend obligation	(328)
Deferred income tax benefit (expense) related to noncredit OTTI losses recognized in AOCI	(11)
Deferred income tax benefit (expense)	(717)
Net unrealized investment gains (losses)	17,772
Net unrealized investment gains (losses) attributable to noncontrolling interests	(11)
Balance, end of period	17,761
Change in net unrealized investment gains (losses)	1,537
Change in net unrealized investment gains (losses) attributable to noncontrolling interests	(11)
Change in net unrealized investment gains (losses) attributable to MetLife, Inc.	$ 1,526

This item presents the increase (decrease) in net unrealized investment gains (losses) attributable to the Company.

No definition available.

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Period Type:	duration

- Definition

This item presents the increase (decrease) in net unrealized investment gains (losses) attributable to noncontrolling interests.

+ References

No definition available.

+ Details

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Period Type:	duration

- Definition

This item presents the increase (decrease) in net unrealized investment gains (losses) excluding portion attributable to noncontrolling interests.

+ References

No definition available.

+ Details

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- Definition

This item presents the increase (decrease) in net unrealized investment gains (losses) related to DAC and VOBA.

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No definition available.

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- Definition

Changes in net unrealized investment gains (losses) related to DAC and VOBA related noncredit OTTI losses recognized in other comprehensive income (loss).

+ References

No definition available.

+ Details

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- Definition

This item presents the increase (decrease) in net unrealized investment gains (losses) on fixed maturity securities on which noncredit OTTI losses have been recognized.

+ References

No definition available.

+ Details

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- Definition

Changes in net unrealized investment gains (losses) related to deferred income tax benefit (expense) related to noncredit OTTI losses recognized in other comprehensive income (loss).

+ References

No definition available.

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- Definition

This item presents the increase (decrease) in net unrealized investment gains (losses) related to insurance liability gain (loss) recognition.

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No definition available.

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- Definition

This item presents the increase (decrease) in net unrealized investment gains (losses) related to policyholder dividend obligation.

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No definition available.

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- Definition

This item presents the increase (decrease) in net unrealized investment gains (losses) related to unrealized investment gains (losses) during the period.

+ References

No definition available.

+ Details

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- Definition

This item represents the tax effects occurring during the period which are related to the net unrealized gain (loss) resulting from changes in the fair [carrying] value during the period of available-for-sale securities and from changes in certain insurance related assets and liabilities. Such tax affects would have been charged or credited directly to other comprehensive income or to related components of shareholders' equity.

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No definition available.

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Period Type:	duration

- Definition

This item presents the net unrealized investment gains (losses) attributable to noncontrolling interests.

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No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
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Period Type:	duration

- Definition

This item presents the net unrealized investment gains (losses) excluding the portion attributable to noncontrolling interests.

+ References

No definition available.

+ Details

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- Definition

This item presents net unrealized investment gains (losses) attributable to the Company.

+ References

No definition available.

+ Details

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