Derivatives (Narrative) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Derivatives, Fair Value [Line Items]
Estimated Fair Value Assets	$ 12,494		$ 12,494		$ 13,452
Estimated Fair Value Liabilities	6,928		6,928		7,022
Maximum Amount of Future Payments under Credit Default Swaps	10,594		10,594		10,527
Estimated Fair Value of Credit Default Swaps	158		158		175
Excess securities collateral received on derivatives	86		86		$ 87
Derivative Instruments, Gain (Loss) [Line Items]
Net derivatives gains (losses)	821	$ 229	$ 794	$ 120
Derivative, Average Remaining Maturity			4 years		3 years 11 months
Gain (Loss) on Investments	133	125	$ (153)	536
Derivative Instrument Detail [Abstract]
Net amounts reclassified into net derivatives gains (losses) on discontinued cash flow hedges	3	$ (2)	$ 3	$ (4)
Hedging exposure to variability in future cash flows for specific length of time			6 years		6 years
Accumulated Other Comprehensive Income Loss	1,800		$ 1,800		$ 1,800
Deferred net gains (losses) expected to be reclassified to earnings			9
Amount and Location of Gains (Losses) Reclassified from Accumulated Other Comprehensive Income (Loss) into Income (Loss) (Effective Portion)	$ 0		$ 0
Immateriality of cash flow effectiveness	0	0	0	0
Cumulative foreign currency translation gain (loss) recorded in accumulated other comprehensive income (loss) for net investment in foreign operations hedges	$ 1,100		$ 1,100		940
Potential future recoveries available to offset maximum amount of future payments under credit default swaps	195		195		75
Excess securities collateral provided on derivatives	285		285		192
Change in fair value of derivatives excluded from the assessment of hedge effectiveness	(3)	$ 2	(5)	$ 5
Securities collateral received which the company is permitted to sell or repledge, amount that has been sold or repledged	0		0
Over the Counter [Member]
Derivatives, Fair Value [Line Items]
Cash collateral on derivative assets	(4,492)		(4,492)		(4,153)
Excess securities collateral received on derivatives	(82)		(82)		(395)
Excess securities collateral provided on derivatives	(149)		(149)		(117)
Exchange-traded
Derivatives, Fair Value [Line Items]
Cash collateral on derivative assets	0		0		0
Excess securities collateral received on derivatives	(227)		(227)		(199)
Excess securities collateral provided on derivatives	(84)		(84)		(245)
Hedge Funds [Member]
Derivatives, Fair Value [Line Items]
Maximum Amount of Future Payments under Credit Default Swaps	104		104		15
Estimated Fair Value of Credit Default Swaps	4		4		1
Ba [Member]
Derivatives, Fair Value [Line Items]
Maximum Amount of Future Payments under Credit Default Swaps	165		165		160
Estimated Fair Value of Credit Default Swaps	1		$ 1		$ (1)
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Average Remaining Maturity			1 year 11 months		2 years 5 months
Nonperformance Risk [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net derivatives gains (losses)	(100)	(51)	$ (31)	(8)
B
Derivatives, Fair Value [Line Items]
Maximum Amount of Future Payments under Credit Default Swaps	694		694		$ 625
Estimated Fair Value of Credit Default Swaps	42		$ 42		$ 39
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Average Remaining Maturity			4 years 11 months		4 years 11 months
Accrued Liabilities [Member]
Derivatives, Fair Value [Line Items]
Estimated Fair Value Assets	249		$ 249		$ 255
Estimated Fair Value Liabilities	66		66		60
Off-Balance Sheet [Member]
Derivatives, Fair Value [Line Items]
Excess securities collateral received on derivatives	0		0		36
Off-Balance Sheet [Member] | Over the Counter [Member]
Derivatives, Fair Value [Line Items]
Cash collateral on derivative assets	0		0		(263)
MetLife Assurance Limited | Accumulated Other Comprehensive Income (Loss) Foreign Currency Translation Adjustments [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Investments		$ (77)		$ (77)
Credit Index Product [Member] | Ba [Member]
Derivatives, Fair Value [Line Items]
Maximum Amount of Future Payments under Credit Default Swaps	100		100		100
Estimated Fair Value of Credit Default Swaps	1		$ 1		(1)
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Average Remaining Maturity			1 year 6 months	2 years
Credit Index Product [Member] | B
Derivatives, Fair Value [Line Items]
Maximum Amount of Future Payments under Credit Default Swaps	694		$ 694		625
Estimated Fair Value of Credit Default Swaps	42		$ 42		$ 39
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Average Remaining Maturity			4 years 11 months		4 years 11 months
Credit Default Swap [Member] | Ba [Member]
Derivatives, Fair Value [Line Items]
Maximum Amount of Future Payments under Credit Default Swaps	65		$ 65		$ 60
Estimated Fair Value of Credit Default Swaps	0		$ 0		$ 0
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Average Remaining Maturity			2 years 7 months		3 years
Credit Default Swap [Member] | B
Derivatives, Fair Value [Line Items]
Maximum Amount of Future Payments under Credit Default Swaps	0		$ 0		$ 0
Estimated Fair Value of Credit Default Swaps	$ 0		$ 0		$ 0
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Average Remaining Maturity