Derivatives (Narrative) (Details) (USD $)	3 Months Ended		12 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Derivatives, Fair Value [Line Items]
Estimated Fair Value Assets	$ 9,130,000,000		$ 8,595,000,000
Estimated Fair Value Liabilities	5,745,000,000		6,521,000,000
Maximum Amount of Future Payments under Credit Default Swaps	9,848,000,000		9,055,000,000
Estimated Fair Value of Credit Default Swaps	139,000,000		165,000,000
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Average Remaining Maturity	3 years 6 months		3 years 5 months
Embedded derivatives	(109,000,000)	1,684,000,000
Derivative Instrument Detail [Abstract]
Net amounts reclassified into net derivatives gains (losses) on discontinued cash flow hedges	(2,000,000)	0
Hedging exposure to variability in future cash flows for specific length of time	7 years		7 years
Accumulated Other Comprehensive Income Loss	642,000,000		375,000,000
Deferred net gains (losses) expected to be reclassified to earnings	(8,000,000)
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
Cumulative foreign currency translation gain (loss) recorded in accumulated other comprehensive income (loss) for net investment in foreign operations hedges	85,000,000		233,000,000
Potential future recoveries available to offset maximum amount of future payments under credit default swaps	55,000,000		90,000,000
Excess securities collateral received on derivatives	102,000,000		104,000,000
Excess securities collateral provided on derivatives	250,000,000		236,000,000
Change in fair value of derivatives excluded from the assessment of hedge effectiveness	3,000,000	0
Securities collateral received which the company is permitted to sell or repledge, amount that has been sold or repledged	0
Over the Counter [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Excess securities collateral received on derivatives	247,000,000		238,000,000
Excess securities collateral provided on derivatives	41,000,000		66,000,000
Exchange Traded [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Excess securities collateral received on derivatives	135,000,000		141,000,000
Excess securities collateral provided on derivatives	63,000,000		81,000,000
Ba [Member]
Derivatives, Fair Value [Line Items]
Maximum Amount of Future Payments under Credit Default Swaps	5,000,000		5,000,000
Estimated Fair Value of Credit Default Swaps	0		0
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Average Remaining Maturity	3 years 6 months		3 years 9 months
Nonperformance Risk [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Embedded derivatives	43,000,000	(414,000,000)
B [Member]
Derivatives, Fair Value [Line Items]
Maximum Amount of Future Payments under Credit Default Swaps	375,000,000		375,000,000
Estimated Fair Value of Credit Default Swaps	29,000,000		32,000,000
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Average Remaining Maturity	5 years 1 month		4 years 11 months
Hedge Funds [Member]
Derivatives, Fair Value [Line Items]
Maximum Amount of Future Payments under Credit Default Swaps	15,000,000		10,000,000
Estimated Fair Value of Credit Default Swaps	0		0
Accrued Liabilities [Member]
Derivatives, Fair Value [Line Items]
Estimated Fair Value Assets	233,000,000		255,000,000
Estimated Fair Value Liabilities	48,000,000		28,000,000
Credit Index Product [Member] | Ba [Member]
Derivatives, Fair Value [Line Items]
Maximum Amount of Future Payments under Credit Default Swaps	0		0
Estimated Fair Value of Credit Default Swaps	0		0
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Average Remaining Maturity	0 years		0 years
Credit Index Product [Member] | B [Member]
Derivatives, Fair Value [Line Items]
Maximum Amount of Future Payments under Credit Default Swaps	375,000,000		375,000,000
Estimated Fair Value of Credit Default Swaps	29,000,000		32,000,000
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Average Remaining Maturity	5 years 1 month		4 years 11 months
Credit Default Swap [Member] | Ba [Member]
Derivatives, Fair Value [Line Items]
Maximum Amount of Future Payments under Credit Default Swaps	5,000,000		5,000,000
Estimated Fair Value of Credit Default Swaps	0		0
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Average Remaining Maturity	3 years 6 months		3 years 9 months
Credit Default Swap [Member] | B [Member]
Derivatives, Fair Value [Line Items]
Maximum Amount of Future Payments under Credit Default Swaps	0		0
Estimated Fair Value of Credit Default Swaps	$ 0		$ 0
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Average Remaining Maturity	0 years		0 years