Consolidated Balance Sheets (USD $) In Millions	Sep. 30, 2011	Dec. 31, 2010
Current assets:
Cash and cash equivalents	$ 217.1	$ 85.4
Accounts receivable, net	186.9	160.0
Materials and supplies	116.0	101.4
Deferred income taxes	132.1	138.2
Other current assets	71.6	91.2
Total current assets	723.7	576.2
Investments	55.2	46.4
Restricted funds	15.4	22.0
Property and equipment (including concession assets), net	5,159.5	4,902.4
Other assets	112.2	93.9
Total assets	6,066.0	5,640.9
Current liabilities:
Debt due within one year	36.3	18.1
Accounts payable and accrued liabilities	400.6	403.0
Total current liabilities	436.9	421.1
Long-term debt	1,676.2	1,621.6
Deferred income taxes	768.4	654.5
Other noncurrent liabilities and deferred credits	229.6	230.0
Total liabilities	3,111.1	2,927.2
Commitments and contingencies	0	0
Stockholders' equity:
$.01 par, common stock, 400,000,000 shares authorized; 123,352,185 and 116,352,298 shares issued at September 30, 2011 and December 31, 2010, respectively; 109,844,141 and 102,648,845 shares outstanding at September 30, 2011 and December 31, 2010, respectively	1.1	1.0
Paid-in capital	884.0	877.2
Retained earnings	1,779.7	1,548.0
Accumulated other comprehensive loss	(1.9)	(1.4)
Total stockholders’ equity	2,669.0	2,431.1
Noncontrolling interest	285.9	282.6
Total equity	2,954.9	2,713.7
Total liabilities and equity	6,066.0	5,640.9
Series D [Member]
Stockholders' equity:
Preferred Stock	0	0.2
$25 Par Preferred Stock [Member]
Stockholders' equity:
Preferred Stock	$ 6.1	$ 6.1