Earnings Per Share - Narrative (Details) (USD $) Share data in Millions, unless otherwise specified			3 Months Ended						3 Months Ended			3 Months Ended								1 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Dec. 31, 2012 Common Stock	Mar. 31, 2012 Common Stock	Dec. 31, 2012 Convertible Subordinated Debt	Sep. 30, 2012 Convertible Subordinated Debt	Dec. 31, 2012 Senior Notes	Sep. 30, 2012 Senior Notes	Dec. 31, 2012 TEU Senior Amortizing Notes Maturing August 2013 [Member]	Dec. 31, 2012 TEU Senior Amortizing Notes Maturing August 2013 [Member] Senior Notes	Sep. 30, 2012 TEU Senior Amortizing Notes Maturing August 2013 [Member] Senior Notes	Mar. 31, 2012 7 1/2% Mandatory Convertible Subordinated Notes [Member] Convertible Subordinated Debt	Dec. 31, 2011 7 1/2% Mandatory Convertible Subordinated Notes [Member] Convertible Subordinated Debt	Dec. 31, 2012 Tangible Equity Units	Mar. 31, 2012 Tangible Equity Units TEUs	Jul. 17, 2012 Tangible Equity Units Senior Notes TEUs	Mar. 31, 2012 Tangible Equity Units Senior Notes TEUs	May 31, 2010 Tangible Equity Units Senior Notes TEUs	Dec. 31, 2011 SSARs / Stock Options [Member]	Jan. 25, 2013 Subsequent Event Common Stock	Jan. 15, 2013 Subsequent Event 7 1/2% Mandatory Convertible Subordinated Notes [Member] Convertible Subordinated Debt
Earnings Per Share [Line Items]
Debt Conversion, Converted Instrument, Shares Issued			0.6	2.2																0.4
Value of convertible debt exchanged for common stock												$ 48,100,000
Shares exchanged for common stock				2.8
Tangible Equity Units (TEUs) issued during period, (units)															4,600,000	4,600,000	2,800,000	3,000,000
Long-term debt	1,496,951,000	1,498,198,000			9,402,000	9,402,000	1,199,344,000	1,201,067,000													9,400,000
Tangible Equity Units outstanding									22.0					4.8
Senior notes										$ 239,000	$ 316,000
Shares of common stock issuable upon conversion									0.4					8.1
Stock Issued During Period, Shares, Conversion of Convertible Securities													2.5	8.1
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Outstanding Options																			0.5