CONSOLIDATED BALANCE SHEETS (USD $) In Millions, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Current assets:
Cash and cash equivalents	$ 1,713.3	$ 1,207.0
Accounts receivable - net	464.9	269.4
Inventories - net	265.5	304.2
Other	14.7	18.0
Total current assets	2,458.4	1,798.6
Property, plant and equipment, net of accumulated depreciation, depletion and amortization of $2,534.4 and $2,447.5	3,712.5	3,736.0
Asset retirement obligation funds	147.6	145.4
Investments in and advances to affiliates	934.7	928.6
Investments in auction rate securities	71.1	70.9
Goodwill	2,064.5	2,064.5
Other assets	228.1	230.5
Total assets	9,616.9	8,974.5
Current liabilities:
Accounts payable and accrued expenses	319.3	327.7
Income taxes payable	139.7	128.5
Customer advances	399.9	257.2
Deferred income taxes	106.7	90.1
Distributions payable to noncontrolling interest	153.1	149.7
Other	131.8	78.0
Total current liabilities	1,250.5	1,031.2
Notes payable	4.9	4.8
Long-term debt	1,613.0	1,613.0
Deferred income taxes	948.2	956.8
Other noncurrent liabilities	439.4	435.8
Contingencies (Note 21)
Stockholders' equity:
Preferred stock - $0.01 par value, 50,000,000 shares authorized
Common stock - $0.01 par value, 500,000,000 shares authorized, 2012 - 72,101,077 and 2011 - 71,935,838 shares issued	0.7	0.7
Paid-in capital	2,820.2	2,804.8
Retained earnings	3,183.2	2,841.0
Treasury stock - at cost, 2012 and 2011 - 6,515,251 shares	(1,000.2)	(1,000.2)
Accumulated other comprehensive loss	(72.0)	(99.3)
Total stockholders' equity	4,931.9	4,547.0
Noncontrolling interest	429.0	385.9
Total equity	5,360.9	4,932.9
Total liabilities and equity	$ 9,616.9	$ 8,974.5