Long-Term Debt (Details)	12 Months Ended						12 Months Ended						12 Months Ended														12 Months Ended						12 Months Ended
	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Dec. 31, 2012 USD ($)	Dec. 31, 2014 Revolving Credit Agreement [Member] USD ($)	Dec. 31, 2014 Canadian Dollar Letter of Credit Facilities Due 2018 [Member] USD ($)	Dec. 31, 2014 Canadian Dollar Letter of Credit Facilities Due 2018 [Member] CAD	Dec. 31, 2014 Uncommitted Credit Facilities [Member] USD ($)	Dec. 31, 2013 Uncommitted Credit Facilities [Member] USD ($)	Dec. 31, 2014 Commercial Paper [Member] USD ($)	Dec. 31, 2013 Commercial Paper [Member] USD ($)	Dec. 31, 2014 2.625% Senior Notes due 2023 USD ($)	Dec. 31, 2013 2.625% Senior Notes due 2023 USD ($)	Dec. 31, 2014 Floating Rate Senior Notes due 2014 USD ($)	Dec. 31, 2013 Floating Rate Senior Notes due 2014 USD ($)	Dec. 31, 2014 2.95% Senior Notes due 2015 USD ($)	Dec. 31, 2013 2.95% Senior Notes due 2015 USD ($)	Dec. 31, 2014 2.500% Senior Notes due 2016 USD ($)	Dec. 31, 2013 2.500% Senior Notes due 2016 USD ($)	Dec. 31, 2014 5.875% Senior Notes due 2017 USD ($)	Dec. 31, 2013 5.875% Senior Notes due 2017 USD ($)	Dec. 31, 2014 6.875% Senior Notes due 2018 USD ($)	Dec. 31, 2013 6.875% Senior Notes due 2018 USD ($)	Dec. 31, 2014 5.625% Senior Notes due 2019 USD ($)	Dec. 31, 2013 5.625% Senior Notes due 2019 USD ($)	Dec. 31, 2014 4.40% Senior Notes due 2020 USD ($)	Dec. 31, 2013 4.40% Senior Notes due 2020 USD ($)	Dec. 31, 2014 2.45% Senior Notes due 2020 USD ($)	Dec. 31, 2013 2.45% Senior Notes due 2020 USD ($)	Dec. 31, 2014 4.100% Senior Notes due 2021 USD ($)	Dec. 31, 2013 4.100% Senior Notes due 2021 USD ($)	Dec. 31, 2014 6.65% Senior Notes due 2028 USD ($)	Dec. 31, 2013 6.65% Senior Notes due 2028 USD ($)	Dec. 31, 2014 4.75% Subsidiary Debt due 2014 USD ($)	Dec. 31, 2013 4.75% Subsidiary Debt due 2014 USD ($)
Debt Instrument Table [Line Items]
Total Long-Term Debt	$ 5,890,000,000	$ 5,890,000,000									$ 1,250,000,000	$ 1,250,000,000	$ 0	$ 350,000,000	$ 500,000,000	$ 500,000,000	$ 400,000,000	$ 400,000,000	$ 600,000,000	$ 600,000,000	$ 350,000,000	$ 350,000,000	$ 900,000,000	$ 900,000,000	$ 500,000,000	$ 500,000,000	$ 500,000,000	$ 0	$ 750,000,000	$ 750,000,000	$ 140,000,000	$ 140,000,000	$ 0	$ 150,000,000
Capital Lease Obligation	51,221,000	57,187,000
Less: Current Portion of Long-Term Debt	6,579,000	6,579,000
Unamortized Debt Discount	31,288,000	33,966,000
Total Long-Term Debt, Net	5,903,354,000	5,906,642,000
Debt Instrument Issuance [Abstract]
Debt Instrument Issuance Face Amount													350,000,000														500,000,000						150,000,000
Debt Instrument Issuance Interest Rate															2.95%												2.45%						4.75%
Debt Instrument, Maturity Years													2014														2020
Settlement of Foreign Currency																																	32,000,000
Settlement of Interest Rate Swap													800,000
Proceeds From Issuance of Senior Long-Term Debt																											496,000,000
Long-Term Debt by Maturity [Abstract]
Aggregate annual maturity of long-term debt in 2014															500,000,000
Aggregate annual maturity of long-term debt (excluding capital lease obligations) in 2015	500,000,000
Aggregate annual maturity of long-term debt (excluding capital lease obligations) in 2016	400,000,000
Aggregate annual maturity of long-term debt (excluding capital lease obligations) in 2017	600,000,000
Aggregate annual maturity of long-term debt (excluding capital lease obligations) in 2018	350,000,000
Aggregate annual maturity of long-term debt (excluding capital lease obligations) in 2019	900,000,000
Line of Credit Facility [Line Items]
Long-Term Debt Repayments	500,000,000	400,000,000	0
Average Borrowings Outstanding							100,000	0	12,000,000	37,000,000
Borrowings Outstanding				0			0	0	0	0
Weighted average interest rate (in hundredths)							0.70%		0.25%	0.30%
Eurodollar rate at period end (in hundredths)				1.05%
Base rate at period end (in hundredths)				3.25%
Line of Credit Facility, Expiration Date				Oct. 11, 2016
Restricted Cash					150,000,000	170,000,000
Maximum borrowing capacity				$ 2,000,000,000
Maximum total debt-to-total capitalization ratio allowed under financial covenant (in hundredths)				65.00%