Consolidated Balance Sheets - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Current assets:
Cash and cash equivalents	$ 47.6	$ 100.5
Accounts receivable, net	296.3	301.2
Materials and supplies	154.5	160.3
Other current assets	111.3	73.4
Total current assets	609.7	635.4
Operating lease right-of-use assets	193.2	0.0
Investments	48.0	44.9
Property and equipment (including concession assets), net	8,744.6	8,691.1
Other assets	42.6	98.4
Total assets	9,638.1	9,469.8
Current liabilities:
Long-term debt due within one year	283.9	10.1
Accounts payable and accrued liabilities	483.4	436.9
Total current liabilities	767.3	447.0
Long-term operating lease liabilities	103.8	0.0
Long-term debt	2,401.4	2,679.3
Deferred income taxes	1,088.1	1,079.9
Other noncurrent liabilities and deferred credits	126.0	130.9
Total liabilities	4,486.6	4,337.1
Stockholders' equity:
$.01 par, common stock, 400,000,000 shares authorized; 123,352,185 shares issued; 99,877,377 and 100,896,678 shares outstanding at June 30, 2019 and December 31, 2018, respectively	1.0	1.0
Additional paid-in capital	947.1	946.6
Retained earnings	3,898.8	3,870.6
Accumulated other comprehensive loss	(23.3)	(10.9)
Total stockholders’ equity	4,829.2	4,813.0
Noncontrolling interest	322.3	319.7
Total equity	5,151.5	5,132.7
Total liabilities and equity	9,638.1	9,469.8
$25 Par Preferred Stock [Member]
Stockholders' equity:
$25 par, 4% noncumulative, preferred stock, 840,000 shares authorized, 649,736 shares issued; 223,495 and 228,395 shares outstanding at June 30, 2019 and December 31, 2018, respectively	$ 5.6	$ 5.7