Debt (Details 1) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2014	Dec. 31, 2013
Debt Instrument [Line Items]
Short-term Debt, Weighted Average Interest Rate	1.28%	1.70%
Short-term Debt	$ 1,604	$ 1,315
Long-term debt:
Commercial paper	375,949	498,236
Unsecured U.S. notes - Medium-term notes	3,771,238	3,271,734
Unsecured U.S. obligations, principally bank term loans	55,500	55,500
Unsecured foreign obligations	324,423	315,558
Capital lease obligations	36,584	38,911
Total before fair market value adjustment	4,563,694	4,179,939
Fair market value adjustment on notes subject to hedging	7,855	8,171
Total after fair market value adjustment	4,571,549	4,188,110
Current portion of long-term debt, including capital leases	(412,077)	(258,123)
Short-term debt and current portion of long-term debt	557,681	259,438
Long-term debt	4,159,472	3,929,987
Total debt	4,717,153	4,189,425
USCommercialPaperShortTerm [Member]
Debt Instrument [Line Items]
Short-term Debt, Weighted Average Interest Rate	0.26%	0.00%
Unsecured Medium Term Notes Due 2019 [Member]
Debt Instrument [Line Items]
Debt Instrument, Call Feature	101% of principal plus accrued and unpaid interest
U.S Commercial Paper, Long-Term [Member]
Long-term debt:
Long-term debt, Weighted Average Interest Rate	0.26%	0.28%
Maturity date range, end	Oct. 18, 2018
Commercial paper	375,949	486,939
Canadian Commerial Paper [Member]
Long-term debt:
Long-term debt, Weighted Average Interest Rate	0.00%	1.13%
Maturity date range, end	Oct. 18, 2018
Commercial paper	0	11,297
Global Revolving Credit Facility Member
Long-term debt:
Maturity date range, end	Oct. 18, 2018
Unsecured U.S. notes - Medium-term notes, Long-Term [Member]
Long-term debt:
Long-term debt, Weighted Average Interest Rate	3.29%	3.76%
Maturity date range, start	Mar. 01, 2015
Maturity date range, end	Feb. 25, 2025
Unsecured U.S. obligations, principally bank term loans, Long-Term [Member]
Long-term debt:
Long-term debt, Weighted Average Interest Rate	1.44%	1.45%
Maturity date range, start	Mar. 08, 2015
Maturity date range, end	Mar. 19, 2018
Unsecured Foreign Obligations, Long-Term [Member]
Long-term debt:
Long-term debt, Weighted Average Interest Rate	1.99%	1.99%
Maturity date range, start	Mar. 01, 2015
Maturity date range, end	Sep. 06, 2016
Capital Lease Obligations, Long-Term [Member]
Long-term debt:
Long-term debt, Weighted Average Interest Rate	3.69%	3.81%
Maturity date range, start	May 24, 2014
Maturity date range, end	Dec. 28, 2019
USCommercialPaperShortTerm [Member]
Debt Instrument [Line Items]
Commercial Paper	$ 144,000	$ 0