Investments (Fair Value of our Marketable Debt Securities by Contractual Maturity) (Details) (USD $) In Millions	Sep. 30, 2011
Investments, Debt and Equity Securities [Abstract]
Due in one year or less	$ 93
Due after one year through five years	304
Due after five years through ten years	316
Due after ten years	364
Total	$ 1,077

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

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+ Details