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Long-Term Debt - Additional Information (Detail) (USD $)
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12 Months Ended | ||||||||
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Dec. 31, 2012
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Dec. 31, 2011
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Dec. 31, 2012
Senior Notes
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Nov. 30, 2012
Senior Notes
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Dec. 31, 2012
0.65% Notes due on November 27, 2015
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Dec. 31, 2012
1.20% Notes due on November 29, 2017
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Dec. 31, 2012
2.50% Notes due on November 29, 2022
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Dec. 31, 2012
Other Long Term Debt
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Dec. 31, 2011
Other Long Term Debt
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| Debt Instrument [Line Items] | |||||||||
| Face amount | $ 3,000,000,000 | ||||||||
| Number of tranches of debt issued | 3 | ||||||||
| Net carrying mount | 3,000,000,000 | ||||||||
| Unamortized discount | 27,000,000 | ||||||||
| Carrying amount of other long term debt including current portion | 691,000,000 | 384,000,000 | |||||||
| Effective interest yields | 0.84% | 1.38% | 2.66% | ||||||
| Interest payment frequency | Semi-annually in arrears in May and November | ||||||||
| Total estimated fair value of notes | $ 3,000,000,000 | ||||||||
| Long-term debt, weighted average interest rate | 6.40% | 5.90% | |||||||