CONSOLIDATED BALANCE SHEETS (PARENTHETICAL) (USD $) In Millions, except Share data, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013
Assets
Trade receivables, allowance for doubtful accounts	$ 11.5		$ 13.6
Current notes receivable and other receivables, allowance for doubtful accounts	0.8		1.1
Maintenance and operating supplies, allowance for obsolete supplies	5.0		6.8
Properties, accumulated depreciation	1,343.2		1,458.7
Other intangibles, accumulated amortization	359.6		513.7
Notes receivable, allowance for doubtful accounts	1.6		2.8
Due to Affiliate, Current	$ 21.4		$ 22.8
Equity [Abstract]
Preferred stock, non-voting, par value	$ 0		$ 0
Preferred stock, non-voting, authorized shares	25,000,000		25,000,000
Preferred stock, non-voting, issued shares	0		0
Treasury shares	7,500,000		7,500,000
Class A common stock, voting
Equity [Abstract]
Common stock, par value	$ 0.01		$ 0.01
Common stock, authorized shares	500,000,000		500,000,000
Common stock, issued shares	2,600,000		2,600,000
Common stock, outstanding shares	2,600,000		2,600,000
Class B common stock, non-voting
Equity [Abstract]
Common stock, par value	$ 0.01		$ 0.01
Common stock, authorized shares	500,000,000		500,000,000
Common stock, issued shares	169,900,000	[1]	167,200,000	[1]
Class A exchangeable shares
Equity [Abstract]
Exchangeable shares, par value	$ 0		$ 0
Exchangeable shares, issued shares	2,900,000		2,900,000
Exchangeable shares, outstanding shares	2,900,000		2,900,000
Class B exchangeable shares
Equity [Abstract]
Exchangeable shares, par value	$ 0		$ 0
Exchangeable shares, issued shares	17,600,000		19,000,000
Exchangeable shares, outstanding shares	17,600,000		19,000,000

[1] During 2011, we repurchased Class B common shares which results in a lower number of outstanding shares compared to issued shares. See "Share Repurchase Program" below for further discussion. For all other classes, issued shares equal outstanding shares.