Debt and Other Financing (Narrative) (Details) (USD $)	1 Months Ended		3 Months Ended	12 Months Ended																								3 Months Ended																					12 Months Ended	3 Months Ended			3 Months Ended			1 Months Ended		3 Months Ended	12 Months Ended
	Mar. 31, 2009	Mar. 31, 2008	Mar. 31, 2013	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Mar. 31, 2014	Apr. 15, 2013	Mar. 29, 2013	Apr. 30, 2003	Dec. 31, 2013 Two Point Three Seven Five Percent Notes, Due March Two Thousand Sixteen [Member]	Mar. 31, 2013 Two Point Three Seven Five Percent Notes, Due March Two Thousand Sixteen [Member]	Dec. 31, 2012 Two Point Three Seven Five Percent Notes, Due March Two Thousand Sixteen [Member]	Dec. 31, 2013 Four Point Six Zero Percent Notes, Due March Two Thousand Twenty [Member]	Mar. 31, 2013 Four Point Six Zero Percent Notes, Due March Two Thousand Twenty [Member]	Dec. 31, 2012 Four Point Six Zero Percent Notes, Due March Two Thousand Twenty [Member]	Dec. 31, 2013 Five Point Zero Percent Notes, Due March Two Thousand Twenty-Three [Member]	Mar. 31, 2013 Five Point Zero Percent Notes, Due March Two Thousand Twenty-Three [Member]	Dec. 31, 2012 Five Point Zero Percent Notes, Due March Two Thousand Twenty-Three [Member]	Dec. 31, 2013 Term Loan [Member]	Dec. 31, 2012 Term Loan [Member]	Dec. 31, 2013 Four Point Eight Percent Notes, Due March Two Thousand Thirteen [Member]	Dec. 31, 2012 Four Point Eight Percent Notes, Due March Two Thousand Thirteen [Member]	Mar. 31, 2008 Four Point Eight Percent Notes, Due March Two Thousand Thirteen [Member]	Dec. 31, 2013 Four Point Six Two Five Percent Notes, Due May Two Thousand Thirteen [Member]	Dec. 31, 2012 Four Point Six Two Five Percent Notes, Due May Two Thousand Thirteen [Member]	May 31, 2003 Four Point Six Two Five Percent Notes, Due May Two Thousand Thirteen [Member]	Jun. 30, 2013 Five Point Six Two Five Percent Notes, Due March Two Thousand Fourteen [Member]	Mar. 31, 2013 Five Point Six Two Five Percent Notes, Due March Two Thousand Fourteen [Member]	Dec. 31, 2013 Five Point Six Two Five Percent Notes, Due March Two Thousand Fourteen [Member]	Apr. 15, 2013 Five Point Six Two Five Percent Notes, Due March Two Thousand Fourteen [Member]	Dec. 31, 2012 Five Point Six Two Five Percent Notes, Due March Two Thousand Fourteen [Member]	Mar. 31, 2009 Five Point Six Two Five Percent Notes, Due March Two Thousand Fourteen [Member]	Nov. 23, 2010 Two Point Six Percent Notes, Due November Two Thousand Fifteen [Member]	Dec. 31, 2013 Five Point Seven Five Percent Notes, Due March Two Thousand Eighteen [Member]	Dec. 31, 2012 Five Point Seven Five Percent Notes, Due March Two Thousand Eighteen [Member]	Mar. 31, 2008 Five Point Seven Five Percent Notes, Due March Two Thousand Eighteen [Member]	Dec. 31, 2013 Four Point Two Percent Notes, Due July Two Thousand Eighteen [Member]	Dec. 31, 2012 Four Point Two Percent Notes, Due July Two Thousand Eighteen [Member]	Jun. 30, 2003 Four Point Two Percent Notes, Due July Two Thousand Eighteen [Member]	Dec. 31, 2013 Six Point Five Percent Notes, Due March Two Thousand Nineteen [Member]	Dec. 31, 2012 Six Point Five Percent Notes, Due March Two Thousand Nineteen [Member]	Mar. 31, 2009 Six Point Five Percent Notes, Due March Two Thousand Nineteen [Member]	Nov. 23, 2010 Four Point Zero Three Percent Notes, Due November Two Thousand Twenty [Member]	Nov. 23, 2010 Four Point One Eight Percent Notes, Due November Two Thousand Twenty Two [Member]	Dec. 31, 2013 Six Point Nine Five Percent Notes, Due March Two Thousand Forty-Three [Member]	Mar. 31, 2013 Six Point Nine Five Percent Notes, Due March Two Thousand Forty-Three [Member]	Dec. 31, 2012 Six Point Nine Five Percent Notes, Due March Two Thousand Forty-Three [Member]	Dec. 31, 2013 Revolving Credit Facility [Member]	Mar. 31, 2013 2010 Revolving Credit Facility [Member]	Dec. 31, 2012 2010 Revolving Credit Facility [Member]	Dec. 31, 2013 Revolving credit facility and term loan agreement [Member]	Mar. 31, 2013 Private Placement [Member]	Dec. 31, 2013 Private Placement [Member]	Mar. 29, 2013 Private Placement [Member]	Jul. 31, 2013 Term Loan [Member]	Mar. 31, 2013 Term Loan [Member]	Mar. 31, 2014 Term Loan [Member]	Dec. 31, 2013 Term Loan [Member]	Jun. 30, 2012 Term Loan [Member]	Dec. 31, 2013 Line of Credit [Member]
Average annual interest rates				6.50%	8.60%
Increase (Decrease) in Fair Value of Interest Rate Fair Value Hedging Instruments				$ (700,000)	$ (8,400,000)	$ 53,200,000
Obligations under capital leases				11,600,000	13,900,000
Other financing obligations				56,300,000	61,600,000
Financing lease obligations				44,500,000	48,400,000
Net unrealized gains on debt with fair value hedges					93,100,000
Percentage of Debt Hedged by Interest Rate Derivatives					62.00%
Line of Credit Facility, Maximum Borrowing Capacity																																																	1,000,000,000		1,000,000,000									500,000,000
Term loan incremental draw down																																																											50,000,000
Long-term Debt, Maturities, Repayment Terms																																																											Pursuant to the term loan agreement, we are required to repay an amount equal to 25% of the aggregate remaining principal amount of the term loan on June 29, 2014, and the remaining outstanding principal amount of the term loan on June 29, 2015.
Term Loan prepayment percentage of proceeds received from incurrence of debt				50.00%
Amount in excess requiring prepayment of Term Loan				500,000,000
Repayments of Long-term Debt																																																								117,500,000	380,000,000
Loss on extinguishment of debt			(73,000,000)	(86,000,000)	0	0																						(13,000,000)																									(71,400,000)					(1,600,000)
Long-term Line of Credit																				52,500,000	550,000,000																																						52,500,000
Long-term Line of Credit, Noncurrent																																																											39,400,000
Line of Credit, Current																																																											13,100,000
Write off of Deferred Debt Issuance Cost																													1,100,000																					1,200,000			3,400,000
Notes Payable, Noncurrent											249,900,000		0	499,300,000		0	495,500,000		0			0	250,000,000		0	124,000,000				0		499,400,000			249,600,000	249,600,000		249,600,000	249,600,000		347,700,000	347,300,000				249,300,000		0							535,000,000
Private Notes accrued interest paid March 2013									6,900,000
Principal Amount of Debt	850,000,000	500,000,000								100,000,000		250,000,000			500,000,000			500,000,000						250,000,000			125,000,000				500,000,000		500,000,000	142,000,000			250,000,000			250,000,000			350,000,000	290,000,000	103,000,000		250,000,000
Interest rate, stated percentage										6.25%		2.375%			4.60%			5.00%						4.80%			4.625%						5.625%	2.60%			5.75%			4.20%			6.50%	4.03%	4.18%		6.95%
Debt issued for cash										4,000,000
Unamortized discount to face value											100,000			700,000			4,500,000									1,000,000						600,000			400,000	400,000		400,000	400,000		2,300,000	2,700,000				700,000
Private Notes prepayment percent									100.00%
Private Notes Make Whole Premium							68,000,000
2014 Notes prepayment percent								100.00%
2014 Notes acceleration of interest-rate swap gain			9,800,000
2014 Notes accrued interest paid April 2013								3,400,000
2014 Notes Make Whole Premium								21,700,000
Net proceeds used to repay outstanding debt	837,600,000	496,300,000
Limits of subsidiary debt plus existing at February 28, 2013																																																				500,000,000
Minimum compliance of interest coverage ratio, numerator																																																													4
Minimum compliance of interest coverage ratio, denominator																																																													1
Maximum leverage ratio numerator Dec 2013																																																						3.75
Maximum leverage ratio denominator Dec 2013																																																						1
Maximum leverage ratio numerator Dec 2014																																																						3.5
Maximum leverage ratio denominator Dec 2014																																																						1
Revolving Credit Facility interest coverage ratio add back maximum of restructuring or legal or regulatory action																																																				400,000,000
Revolving credit facility draw down amount without violating covenant				1,000,000,000
Commercial Paper																																																	0		0
Commercial Paper Program																																																	1,000,000,000
Credit facility annual fee																																																	2,000,000
Letters of credit outstanding				$ 19,900,000	$ 21,400,000
Debt Instrument, Credit Rating				Our long-term credit ratings are Baa3 (Stable Outlook) with Moody's and BBB- (Negative Outlook) with S&P, which are on the low end of investment grade, and BB (Negative Outlook) with Fitch, which is below investment grade.