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Amortized Cost and Estimated Fair Value of Marketable Securities by Contractual Maturity (Detail) (USD $)
In Millions, unless otherwise specified |
Sep. 30, 2012
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Dec. 31, 2011
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|---|---|---|
| Cost | ||
| Due in one year or less | $ 43 | |
| Due after one year through three years | 242 | |
| Due after three years through five years | 52 | |
| Due after five years | 234 | |
| Marketable Securities, Debt Maturities, Amortized Cost, Total | 571 | |
| Equity securities | 2 | |
| Total Amortized Cost | 573 | 1,232 |
| Estimated Fair Value | ||
| Due in one year or less | 43 | |
| Due after one year through three years | 244 | |
| Due after three years through five years | 53 | |
| Due after five years | 244 | |
| Marketable Securities, Debt Maturities, Fair Value, Total | 584 | |
| Equity securities | 2 | |
| Total Estimated Fair Value | $ 586 |
| X | ||||||||||
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- Definition
Available-for-sale Debt Securities, Fair Value No definition available.
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| X | ||||||||||
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- Definition
Available-for-sale Securities, Debt Maturities, After Five Years, Amortized Cost Basis No definition available.
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- Definition
Available-For-Sale Securities, Debt Maturities, After Five Years, Fair Value No definition available.
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| X | ||||||||||
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- Definition
Available-for-sale Securities, Debt Maturities, After One Through Three Years, Amortized Cost Basis No definition available.
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- Definition
Available-For-Sale Securities, Debt Maturities, After One Year Through Three Years, Fair Value No definition available.
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- Definition
Available-for-sale Securities, Debt Maturities, After Three Through Five Years, Amortized Cost Basis No definition available.
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- Definition
Available-For-Sale Securities, Debt Maturities, After Three Years Through Five Years, Fair Value No definition available.
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| X | ||||||||||
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- Definition
Availalbe-for-Sale Equity Securities, Fair Value No definition available.
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| X | ||||||||||
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- Details
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| X | ||||||||||
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- Details
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| X | ||||||||||
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- Definition
This item represents the cost of debt 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. No definition available.
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| X | ||||||||||
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- Definition
This item represents the cost of equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments for other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any. No definition available.
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| X | ||||||||||
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- Definition
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. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- Definition
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 within one year of the balance sheet date and which are categorized neither as held-to-maturity nor trading securities. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- Definition
This item represents the fair value of debt securities which are expected to mature within one year of the balance sheet date and which are categorized neither as held-to-maturity nor trading securities. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
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- Definition
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. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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