Investments (Details 3) (Fixed Maturity [Member], USD $) In Millions, unless otherwise specified	Mar. 31, 2015
Fixed Maturity [Member]
Amortized Cost Basis, Fiscal Year Maturity [Abstract]
One year or less	$ 958
After one year through five years	4,894
After five years through ten years	9,286
After ten years	4,596
Fixed maturities amortized cost, Subtotal	19,734
ABS (average life of approximately 4-1/2 years)	4,175
MBS (average life of approximately 4-1/2 years)	6,181
Amortized Cost	30,090
Fair Value, Fiscal Year Maturity [Abstract]
One year or less	978
After one year through five years	5,262
After five years through ten years	9,817
After ten years	4,959
Fixed maturities fair value, Subtotal	21,016
ABS (average life of approximately 4-1/2 years)	4,224
MBS (average life of approximately 4-1/2 years)	6,728
Fair Value	$ 31,968
Fair Value Percent, Fiscal Year Maturity [Abstract]
One year or less	3.00%
After one year through five years	16.00%
After five years through ten years	31.00%
After ten years	16.00%
Fixed maturities fair value, Subtotal, Percent	66.00%
ABS (average life of approximately 4-1/2 years)	13.00%
MBS (average life of approximately 4-1/2 years)	21.00%
Fair value, Total, Percent	100.00%

Asset-backed securities, amortized cost.

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Asset-backed securities, fair value.

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Asset-backed securities, fair value, percent.

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Available-for-sale Securities, Debt Maturities, after Five Through Ten Years, Fair Value, Percent.

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Available-for-sale Securities, Debt Maturities, after One Through Five Years, Fair Value, Percent.

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Available-for-sale Securities, Debt Maturities, after Ten Years, Fair Value, Percent.

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Available for sale securities debt maturities excluding ABS and MBS amortized cost.

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Available for sale securities debt maturities excluding ABS and MBS fair value.

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Available for sale securities debt maturities excluding ABS and MBS fair value percent.

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Available-for-sale Securities, Debt Maturities, Fair Value, Total, Percent.

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Available-for-sale Securities, Debt Maturities, within One Year, Fair Value, Percent.

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Mortgage-backed securities, amortized cost.

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Mortgage-backed securities, fair value, percent.

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Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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Amount after adjustments of available-for-sale debt securities at cost, maturing in the sixth fiscal year through the tenth fiscal year following the latest fiscal year. Adjustments include, but are not limited to, accretion, amortization, collection of cash, previous other-than-temporary impairments (OTTI) recognized in earnings less cumulative-effect adjustments, and fair value hedge accounting adjustments. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Fair value of available-for-sale debt securities maturing in the sixth fiscal year through the tenth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount after adjustments of available-for-sale debt securities at cost, maturing in the second fiscal year through the fifth fiscal year following the latest fiscal year. Adjustments include, but are not limited to, accretion, amortization, collection of cash, previous other-than-temporary impairments (OTTI) recognized in earnings less cumulative-effect adjustments, and fair value hedge accounting adjustments. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Fair value of available-for-sale debt securities maturing in the second fiscal year through the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount after adjustments of available-for-sale debt securities at cost, maturing after the tenth fiscal year following the latest fiscal year. Adjustments include, but are not limited to, accretion, amortization, collection of cash, previous other-than-temporary impairments (OTTI) recognized in earnings less cumulative-effect adjustments, and fair value hedge accounting adjustments. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Fair value of available-for-sale debt securities maturing after the tenth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount after adjustments of available-for-sale debt securities at cost, maturing in the next fiscal year following the latest fiscal year. Adjustments include, but are not limited to, accretion, amortization, collection of cash, previous other-than-temporary impairments (OTTI) recognized in earnings less cumulative-effect adjustments, and fair value hedge accounting adjustments. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Fair value of available-for-sale debt securities maturing in the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Fair value of securitized, pay-through debt securities collateralized by real estate mortgage loans classified as available-for-sale.

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-Glossary Mortgage-Backed Securities

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