Significant Accounting Policies Investment (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011
Schedule Of Marketable Securities Line Items
Marketable Securities	$ 72
Trading Securities	59
Held To Maturity Securities Debt Maturities [Abstract]
Held To Maturity Securities Debt Maturities Within One Year Net Carrying Amount	2
Investments All Other Investments [Abstract]
Restricted Cash And Investments Current	3
Cost Method Investments	2
Cash Equivalents [Member]
Schedule Of Marketable Securities Line Items
Marketable Securities	9
Short Term Investments [Member]
Schedule Of Marketable Securities Line Items
Marketable Securities	53
Long Term Investments [Member]
Schedule Of Marketable Securities Line Items
Marketable Securities	10
Corporate Debt Securities [Member]
Schedule Of Marketable Securities Line Items
Marketable Securities	6
Money Market Funds [Member]
Schedule Of Marketable Securities Line Items
Marketable Securities	59
Other Securities [Member]
Schedule Of Marketable Securities Line Items
Marketable Securities	7
Categories Of Investments Marketable Securities Held To Maturity Securities [Member]
Held To Maturity Securities Debt Maturities [Abstract]
Held To Maturity Securities Debt Maturities After One Through Five Years Net Carrying Amount	5
Held To Maturity Securities Debt Maturities After Five Through Ten Years Net Carrying Amount	1
Held To Maturity Securities Debt Maturities Net Carrying Amount	$ 8

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This item represents the aggregate carrying amount of all cost-method investments as reported on or included in the balance sheet. The original cost of the investments may differ from the aggregate carrying amount disclosed due to various adjustments such as: (i) dividends received in excess of earnings after the date of investment that are considered a return of investment and therefore recorded as reductions to cost of the investment, or (ii) a series of operating losses of an investee or other factors which may indicate that a decrease in value of the investment has occurred which is other than temporary and accordingly such decrease in value has been recognized.

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Total debt and equity financial instruments including: (1) securities held-to-maturity, (2) trading securities, and (3) securities available-for-sale.

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The total of financial instruments that are bought and held principally for the purpose of selling them in the near term (thus held for only a short period of time) or for debt and equity securities formerly categorized as available-for-sale or held-to-maturity which the entity held as of the date it opted to account for such securities at fair value. An enterprise may also categorize such a security as trading without the intent to sell it in the near term assuming the decision to categorize the security as trading occurred at acquisition.

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