Debt (Details) (USD $) In Millions	Jun. 30, 2011	Dec. 31, 2010
Debt
Debt	$ 7,305.5	$ 6,743.6
Less: Current portion	(397.8)	(878.5)
Long-term portion	6,907.7	5,865.1
Senior notes, fixed interest rate of 6.750%, due August 2011 [Member]
Debt
Debt	388.0	392.0
$600.0 million 7.125% senior notes due May 2016 [Member]
Debt
Debt	0	535.5
Senior notes, fixed interest rate of 6.875%, due June 2017 [Member]
Debt
Debt	669.1	663.9
Senior notes, fixed interest rate of 6.200%, due March 2040 [Member]
Debt
Debt	649.5	649.5
$99.5 million 9.250% debentures due May 2021 [Member]
Debt
Debt	33.2	93.4
Debentures, fixed interest rate of 7.400%, due September 2035 [Member]
Debt
Debt	132.0	267.6
Senior notes, fixed interest rate of 5.500%, due September 2019 [Member]
Debt
Debt	646.0	645.8
Senior notes, fixed interest rate of 6.086%, due March 2035 [Member]
Debt
Debt	250.1	249.8
Senior notes, fixed interest rate of 3.800%, due 2018 [Member]
Debt
Debt	699.8	0
Senior notes, fixed interest rate of 4.750%, due 2023 [Member]
Debt
Debt	548.6	0
Senior notes, fixed interest rate of 5.700%, due 2041 [Member]
Debt
Debt	596.6	0
Tax-exempt bonds and other tax-exempt financings; fixed and floating interest rates ranging from 0.08% to 8.25%; maturities ranging from 2013 to 2035 [Member]
Debt
Debt	1,151.7	1,151.8
Other debt unsecured and secured by real property, equipment and other assets; interest rates ranging from 5.00% to 11.90% maturing through 2042 [Member]
Debt
Debt	91.0	92.6
Senior notes, fixed interest rate of 5.250%, due November 2021 [Member]
Debt
Debt	600.0	600.0
$1.0 billion Revolver due 2012 [Member]
Debt
Debt	0	50.0
Eurodollar Rate borrowings [Member]
Debt
Debt	0	75.0
Senior notes, fixed interest rate of 5.750%, due February 2011 [Member]
Debt
Debt	0	261.7
$1.75 billion Revolver due 2013, amended to $1.25 billion due 2013 [Member]
Debt
Debt	0	25.0
Senior notes, fixed interest rate of 6.375%, due April 2011 [Member]
Debt
Debt	0	215.1
Senior notes, fixed interest rate of 5.000%, due March 2020 [Member]
Debt
Debt	$ 849.9	$ 849.9