Debt - Summary of outstanding debt (Details)
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Dec. 31, 2014
USD ($)
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Dec. 31, 2013
USD ($)
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Dec. 31, 2014
2.875% notes due 2026 [Member]
USD ($)
|
Dec. 31, 2013
2.875% notes due 2026 [Member]
USD ($)
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Dec. 31, 2014
3.50% senior notes due September 2015 [Member]
USD ($)
|
Dec. 31, 2013
3.50% senior notes due September 2015 [Member]
USD ($)
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Dec. 31, 2014
5.00% Senior notes due September 2020 [Member]
USD ($)
|
Dec. 31, 2013
5.00% Senior notes due September 2020 [Member]
USD ($)
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Dec. 31, 2014
3.50% senior notes due June 2024 [Member]
USD ($)
|
Dec. 31, 2013
3.50% senior notes due June 2024 [Member]
USD ($)
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Dec. 31, 2014
4.60% notes due 2044 [Member]
USD ($)
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Dec. 31, 2013
4.60% notes due 2044 [Member]
USD ($)
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Dec. 31, 2014
8.205% junior subordinated deferrable interest debentures due January 2027 [Member]
USD ($)
|
Dec. 31, 2013
8.205% junior subordinated deferrable interest debentures due January 2027 [Member]
USD ($)
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Dec. 31, 2012
8.205% junior subordinated deferrable interest debentures due January 2027 [Member]
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Dec. 31, 2014
3.125% senior notes due May 2016 [Member]
USD ($)
|
Dec. 31, 2013
3.125% senior notes due May 2016 [Member]
USD ($)
|
Dec. 31, 2014
4.00% senior notes dues November 2023 [Member]
USD ($)
|
Dec. 31, 2013
4.00% senior notes dues November 2023 [Member]
USD ($)
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Nov. 21, 2013
4.00% senior notes dues November 2023 [Member]
USD ($)
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Dec. 31, 2014
4.76% CAD 375 debt securities due March 2018 [Member]
USD ($)
|
Dec. 31, 2014
4.76% CAD 375 debt securities due March 2018 [Member]
CAD
|
Dec. 31, 2013
4.76% CAD 375 debt securities due March 2018 [Member]
USD ($)
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Dec. 31, 2014
6.25% Senior notes due September 2040 [Member]
USD ($)
|
Dec. 31, 2013
6.25% Senior notes due September 2040 [Member]
USD ($)
|
Dec. 31, 2014
4.45% senior notes due May 2043 [Member]
USD ($)
|
Dec. 31, 2013
4.45% senior notes due May 2043 [Member]
USD ($)
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May 21, 2013
4.45% senior notes due May 2043 [Member]
USD ($)
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Dec. 31, 2014
4.25% senior notes due December 2042 [Member]
USD ($)
|
Dec. 31, 2013
4.25% senior notes due December 2042 [Member]
USD ($)
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Apr. 15, 2013
4.25% senior notes due December 2042 [Member]
USD ($)
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Mar. 08, 2013
4.25% senior notes due December 2042 [Member]
USD ($)
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Dec. 12, 2012
4.25% senior notes due December 2042 [Member]
USD ($)
|
Dec. 31, 2014
6.25% EUR 500 debt securities due July 2014 [Member]
USD ($)
|
Dec. 31, 2014
6.25% EUR 500 debt securities due July 2014 [Member]
EUR (€)
|
Dec. 31, 2013
6.25% EUR 500 debt securities due July 2014 [Member]
USD ($)
|
Dec. 31, 2014
Commercial Paper [Member]
USD ($)
|
Dec. 31, 2013
Commercial Paper [Member]
USD ($)
|
Dec. 31, 2014
Other [Member]
USD ($)
|
Dec. 31, 2013
Other [Member]
USD ($)
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Debt Instrument [Line Items] | ||||||||||||||||||||||||||||||||||||||||
Total debt | $ 5,582,000,000 | $ 4,389,000,000 | $ 605,000,000 | $ 0 | $ 599,000,000 | $ 599,000,000 | $ 599,000,000 | $ 599,000,000 | $ 597,000,000 | $ 0 | $ 549,000,000 | $ 0 | $ 521,000,000 | $ 521,000,000 | $ 500,000,000 | $ 500,000,000 | $ 349,000,000 | $ 349,000,000 | $ 322,000,000 | $ 352,000,000 | $ 298,000,000 | $ 298,000,000 | $ 248,000,000 | $ 248,000,000 | $ 196,000,000 | $ 195,000,000 | $ 0 | $ 685,000,000 | $ 168,000,000 | $ 0 | $ 31,000,000 | $ 43,000,000 | ||||||||
Less short-term and current portion of long-term debt | 783,000,000 | 703,000,000 | ||||||||||||||||||||||||||||||||||||||
Long-term debt | 4,799,000,000 | 3,686,000,000 | ||||||||||||||||||||||||||||||||||||||
Interest rate on debt | 2.875% | 3.50% | 5.00% | 3.50% | 4.60% | 8.205% | 8.205% | 3.125% | 4.00% | 4.00% | 4.76% | 4.76% | 6.25% | 4.45% | 4.45% | 4.25% | 4.25% | 4.25% | 4.25% | 6.25% | 6.25% | |||||||||||||||||||
Debt face value | $ 350,000,000 | 375,000,000 | $ 250,000,000 | $ 256,000,000 | $ 90,000,000 | $ 166,000,000 | € 500,000,000 |