Investments (Amortized Cost and Fair Value of Available-for-Sale Debt Securities by Contractual Maturity) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011
Due in one year or less, Amortized Cost	$ 2,629
Due after one year through five years, Amortized Cost	5,631
Due after five years through ten years, Amortized Cost	4,439
Due after ten years, Amortized Cost	1,808
Total debt securities - available-for-sale, Amortized Cost	17,262
Due in one year or less, Fair Value	2,641
Due after one year through five years, Fair Value	5,808
Due after five years through ten years, Fair Value	4,763
Due after ten years, Fair Value	1,933
Total debt securities - available-for-sale, Fair Value	18,002
U.S. Agency Mortgage-Backed Securities [Member]
Mortgage-backed securities, Amortized Cost	2,279
Mortgage-backed securities, Fair Value	2,353
Non-U.S. Agency Mortgage-Backed Securities [Member]
Mortgage-backed securities, Amortized Cost	476
Mortgage-backed securities, Fair Value	$ 504

This item represents debt securities, at cost, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments, as defined), and fair value hedge accounting adjustments, if any, which are expected to mature after five years and through ten years from the balance sheet date and which are categorized neither as held-to-maturity nor trading securities.

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For an unclassified balance sheet, total of debt securities categorized neither as held-to-maturity nor trading.

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