Schedule II Valuation and Qualifying Accounts and Reserves (in millions): (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Accounts Receivable:
Reserve deducted in balance sheet to which applicable:
Balance at beginning of period			$ 4.6
Deduction/Application			4.6
Notes issued under par:
Reserve deducted in balance sheet to which applicable:
Balance at beginning of period	25.4	25.9	16.1
Charged to costs and expenses	0.5	0.5	0.5
Additions	22.4		10.3
Balance at end of period	47.3	25.4	25.9
Deferred Tax Assets:
Reserve deducted in balance sheet to which applicable:
Balance at beginning of period	2.2	30.0	30.5
Deduction/Application	2.2	27.8	0.5
Balance at end of period		$ 2.2	$ 30.0