Investments (Available-For-Sale Securities By Contractual Maturities) (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Available-for-sale Securities, Debt Maturities, Amortized Cost
Available-for-sale securities, Amortized Cost	$ 74,888	$ 73,352
Available-for-sale Securities, Debt Maturities, Fair Value
Fair Value	83,567	82,901
Subtotal [Member]
Available-for-sale Securities, Debt Maturities, Amortized Cost
Available-for-sale securities, Amortized Cost	68,450
Available-for-sale Securities, Debt Maturities, Fair Value
Fair Value	76,704
Fixed Maturity Securities [Member]
Available-for-sale Securities, Debt Maturities, Amortized Cost
Due in one year or less	2,468
Due after one year through five years	12,878
Due after five years through ten years	25,137
Due after ten years	27,967
Available-for-sale securities, Amortized Cost	74,757	73,395
Available-for-sale Securities, Debt Maturities, Fair Value
Due in one year or less	2,518
Due after one year through five years	14,081
Due after five years through ten years	27,924
Due after ten years	32,181
Fair Value	83,419	82,744
Equity AFS Securities [Member]
Available-for-sale Securities, Debt Maturities, Amortized Cost
Available-for-sale securities, Amortized Cost	131	137
Available-for-sale Securities, Debt Maturities, Fair Value
Fair Value	148	157
MBS [Member] \| Fixed Maturity Securities [Member]
Available-for-sale Securities, Debt Maturities, Amortized Cost
Available-for-sale securities, Amortized Cost	6,126
Available-for-sale Securities, Debt Maturities, Fair Value
Fair Value	6,542
CDOs [Member] \| Fixed Maturity Securities [Member]
Available-for-sale Securities, Debt Maturities, Amortized Cost
Available-for-sale securities, Amortized Cost	181	189
Available-for-sale Securities, Debt Maturities, Fair Value
Fair Value	$ 173	$ 180

This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

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Amount of available-for-sale debt securities at cost, net of adjustments, 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 any cumulative-effect adjustments, as defined) and fair value hedge accounting adjustments.

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Amount of available-for-sale debt securities at fair value maturing in the second fiscal year through the fifth fiscal year following the latest fiscal year.

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Amount of available-for-sale debt securities at cost, net of adjustments, 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 any cumulative-effect adjustments, as defined) and fair value hedge accounting adjustments.

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This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item represents Available-for-sale Securities which consist of all investments in certain debt and equity securities neither classified as trading or held-to-maturity securities. A debt security represents a creditor relationship with an enterprise. Debt securities include, among other items, US Treasury securities, US government securities, municipal securities, corporate bonds, convertible debt, commercial paper, and all securitized debt instruments. An equity security represents an ownership interest in an enterprise or the right to acquire or dispose of an ownership interest in an enterprise at fixed or determinable prices. Equity securities include, among other things, common stock, certain preferred stock, warrant rights, call options, and put options, but do not include convertible debt. An entity may opt to provide the reader with additional narrative text to better understand the nature of investments in debt and equity securities which are categorized as Available-for-sale.

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