Senior Notes (Tables)

12 Months Ended

Dec. 31, 2012

Summary of Fixed-Rate Senior Notes

Carrying Value at December 31,					Coupon Rate at December 31, 2012	Effective Interest Rate at December 31, 2012	Maturity Date at December 31, 2012
	2012		2011
Unsecured indebtedness:
Senior Notes	$	1,825.2	$	1,658.6		4.625% – 9.625%	4.8% – 9.9%	May 2015 - July 2022
Senior Notes — Premium (Discount), net		4.0		(5.4	)
Senior Convertible Notes due 2040, net(A)		317.9		307.6		1.75%	5.3%	November 2040
Senior Convertible Notes due 2012, net		—		178.9		N/A	N/A	N/A
Total Senior Notes	$	2,147.1	$	2,139.7

(A) The Company may redeem the senior convertible notes any time on or after November 15, 2015, in whole or in part, for cash equal to 100% of the principal amount of the notes plus accrued and unpaid interest through, but excluding, the redemption date. In addition, the holders of the senior convertible notes may require the Company to repurchase their notes in whole or in part on specified dates, the first of which is November 15, 2015.

Summary of Carrying Amounts of Debt and Equity Balances

The Company’s carrying amounts of its debt and equity balances for the senior convertible notes are as follows (in thousands):

	December 31,
	2012			2011
Carrying value of equity component	$	52,497		$	69,217
Principal amount of senior convertible notes	$	350,000		$	529,509
Remaining unamortized debt discount		(32,120	)		(43,004	)
Net carrying value of senior convertible notes	$	317,880		$	486,505