|
Debt and lines of credit (Details) (USD $)
|
3 Months Ended | 12 Months Ended | |||
|---|---|---|---|---|---|
|
Dec. 31, 2011
|
Dec. 31, 2011
|
Dec. 31, 2010
|
Dec. 31, 2009
|
Jul. 14, 2011
|
|
| Debt Instrument | |||||
| Line of credit facility, maximum borrowing capacity through August 2012 | $ 920,000,000 | $ 920,000,000 | |||
| Line of credit facility, maximum borrowing capacity until July 2012 | 1,000,000,000 | 1,000,000,000 | |||
| Short-term Debt | |||||
| Repayments of commercial paper | 200,000,000 | 200,000,000 | 0 | 0 | |
| Commercial paper | 999,000,000 | 999,000,000 | 0 | 1,200,000,000 | |
| Debt, Weighted average interest rate | 0.25% | 0.25% | |||
| Long-term Debt | |||||
| Long-term debt, gross | 4,500,000,000 | 4,500,000,000 | |||
| Add net unamortized premium (assumed with National acquisition) | 93,000,000 | 93,000,000 | |||
| Less current portion of long-term debt | (382,000,000) | (382,000,000) | 0 | ||
| Total long-term debt | 4,211,000,000 | 4,211,000,000 | 0 | ||
| Payments of debt issuance costs | 12,000,000 | 0 | 0 | ||
| Interest and debt expense | 42,000,000 | 0 | 0 | ||
| Interest paid | 54,000,000 | ||||
|
Notes payable [Member]
|
|||||
| Long-term Debt | |||||
| Proceeds from issuance of long-term debt | 3,497,000,000 | ||||
| Payments of debt issuance costs | 12,000,000 | ||||
|
Notes payable [Member] | Floating-rate notes due 2013 (swapped to a 0.922% fixed rate)
|
|||||
| Long-term Debt | |||||
| Long-term debt, gross | 1,000,000,000 | 1,000,000,000 | |||
| Debt instrument, description of variable rate basis (in months) | 3 | ||||
| Long-term debt, effective fixed-rate interest rate | 0.922% | 0.922% | |||
|
Notes payable [Member] | Floating-rate notes due 2013 (swapped to a 0.922% fixed rate) | Interest rate swap [Member] | Cash flow hedges [Member]
|
|||||
| Long-term Debt | |||||
| Long-term debt, effective fixed-rate interest rate | 0.922% | 0.922% | |||
|
Notes payable [Member] | Notes due 2013 at 0.875%
|
|||||
| Long-term Debt | |||||
| Long-term debt, gross | 500,000,000 | 500,000,000 | |||
| Long-term debt, stated interest rate | 0.875% | 0.875% | |||
|
Notes payable [Member] | Notes due 2014 at 1.375%
|
|||||
| Long-term Debt | |||||
| Long-term debt, gross | 1,000,000,000 | 1,000,000,000 | |||
| Long-term debt, stated interest rate | 1.375% | 1.375% | |||
|
Notes payable [Member] | Notes due 2016 at 2.375%
|
|||||
| Long-term Debt | |||||
| Long-term debt, gross | 1,000,000,000 | 1,000,000,000 | |||
| Long-term debt, stated interest rate | 2.375% | 2.375% | |||
|
National [Member] | Notes payable [Member]
|
|||||
| Long-term Debt | |||||
| Long-term debt, gross | 1,000,000,000 | 1,000,000,000 | |||
| Long-term debt, fair value | 1,105,000,000 | 1,105,000,000 | |||
|
National [Member] | Notes payable [Member] | Notes due 2012 at 6.15% (assumed with National acquisition)
|
|||||
| Long-term Debt | |||||
| Long-term debt, gross | 375,000,000 | 375,000,000 | |||
| Long-term debt, stated interest rate | 6.15% | 6.15% | |||
|
National [Member] | Notes payable [Member] | Notes due 2015 at 3.95% (assumed with National acquisition)
|
|||||
| Long-term Debt | |||||
| Long-term debt, gross | 250,000,000 | 250,000,000 | |||
| Long-term debt, stated interest rate | 3.95% | 3.95% | |||
|
National [Member] | Notes payable [Member] | Notes due 2017 at 6.60% (assumed with National acquisition)
|
|||||
| Long-term Debt | |||||
| Long-term debt, gross | $ 375,000,000 | $ 375,000,000 | |||
| Long-term debt, stated interest rate | 6.60% | 6.60% | |||