Consolidated Statements of Cash Flows (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013
Operating activities:
Net income	$ 224.2	$ 119.9
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	125.8	107.8
Deferred income taxes	58.4	53.4
Equity in net earnings of unconsolidated affiliates	(11.6)	(9.0)
Share-based compensation	4.4	8.3
Excess tax benefit from share-based compensation	(2.5)	(3.3)
Distributions from unconsolidated affiliates	15.8	6.5
Debt retirement costs	6.6	111.4
Changes in working capital items:
Accounts receivable	(12.4)	(14.0)
Materials and supplies	(4.3)	(12.0)
Other current assets	3.2	(27.0)
Accounts payable and accrued liabilities	(10.6)	(26.9)
Other, net	(0.7)	11.3
Net cash provided by operating activities	396.3	326.4
Investing activities:
Capital expenditures	(268.0)	(265.9)
Purchase or replacement of equipment under operating leases	(294.3)	(155.1)
Property investments in MSLLC	(24.8)	(22.6)
Proceeds from disposal of property	3.6	4.3
Other, net	3.9	(4.9)
Net cash used for investing activities	(579.6)	(444.2)
Financing activities:
Proceeds from commercial paper	5,081.5	0
Repayment of commercial paper	(4,761.1)	0
Proceeds from issuance of long-term debt	175.0	1,403.7
Repayment of long-term debt	(495.4)	(1,203.2)
Dividends paid	(54.8)	(23.8)
Debt costs	(4.1)	(105.7)
Excess tax benefit from share-based compensation	2.5	3.3
Proceeds from employee stock plans	0.4	0.9
Net cash provided by (used for) financing activities	(56.0)	75.2
Cash and cash equivalents:
Net decrease during each period	(239.3)	(42.6)
At beginning of year	429.5	72.6
At end of period	$ 190.2	$ 30.0