Debt (Details) (USD $)	9 Months Ended
	Sep. 30, 2014		Dec. 31, 2013
Short-term debt and current portion of long-term debt:
Short-term debt, Weighted Average Interest Rate	1.08%		1.70%
Short-term debt	$ 2,743,000		$ 1,315,000
Short-term debt and current portion of long-term debt	462,312,000		259,438,000
Long-term debt:
Commercial paper	333,000,000		498,200,000
Line of credit facility	3,000,000		0
Unsecured U.S. notes - Medium-term notes	3,771,695,000	[1]	3,271,734,000	[1]
Unsecured U.S. obligations, principally bank term loans	50,500,000		55,500,000
Unsecured foreign obligations	307,709,000		315,558,000
Capital lease obligations	35,695,000		38,911,000
Total before fair market value adjustment	4,501,567,000		4,179,939,000
Fair market value adjustment on notes subject to hedging	3,247,000	[2]	8,171,000	[2]
Total after fair market value adjustment	4,504,814,000		4,188,110,000
Current portion of long-term debt, including capital leases	(459,569,000)		(258,123,000)
Long-term debt	4,045,245,000		3,929,987,000
Total debt	4,507,557,000		4,189,425,000
Unamortized original issue discounts	8,300,000		8,300,000
Aggregate notional amount of interest rate swaps	600,000,000		400,000,000
U.S Commercial Paper, Long-Term [Member]
Long-term debt:
Long-term debt, Weighted Average Interest Rate	0.26%	[1]	0.28%	[1]
Maturity date range, end	Oct. 18, 2018
Commercial paper	332,968,000	[1]	486,939,000	[1]
Canadian Commerial Paper [Member]
Long-term debt:
Long-term debt, Weighted Average Interest Rate	0.00%	[1]	1.13%	[1]
Maturity date range, end	Oct. 18, 2018
Commercial paper	$ 0	[1]	$ 11,297,000	[1]
Global Revolving Credit Facility Member
Long-term debt:
Long-term debt, Weighted Average Interest Rate	1.23%		0.00%
Unsecured U.S. notes - Medium-term notes, Long-Term [Member]
Long-term debt:
Long-term debt, Weighted Average Interest Rate	3.29%	[1]	3.76%	[1]
Maturity date range, start	Mar. 01, 2016
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	2.01%		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	3.62%		3.81%
Maturity date range, start	Dec. 28, 2014
Maturity date range, end	Dec. 28, 2019
Short-term Debt [Member]
Long-term debt:
Maturity date range, end	Jun. 18, 2015

[1] We had unamortized original issue discounts of $8.3 million and $8.3 million at September 30, 2014 and December 31, 2013, respectively.

[2] The notional amount of executed interest rate swaps designated as fair value hedges was $600 million and $400 million at September 30, 2014 and December 31, 2013, respectively.