LONG-TERM DEBT (Tables)

12 Months Ended

Dec. 31, 2017

Debt Disclosure [Abstract]

Schedule of long-term debt

Long-term debt at December 31 consisted of the following (in millions):

	2017		2016
5% Senior Notes, due September 2017 ($92.2 million principal amount; 5.2% effective rate)	$	—	$	92.0
7.875% Senior Notes, due August 2019 ($201.4 million and $209.8 million principal amount, respectively; 8.0% effective rate)	200.9		208.9
4.875% Senior Notes, due June 2022 ($620.8 million and $690.2 million principal amount, respectively; 4.7% effective rate)	624.6		695.4
4.75% Senior Notes, due January 2024 ($398.1 million principal amount; 4.8% effective rate)	395.9		395.6
7.375% Senior Notes, due June 2025 ($500 million principal amount; 7.4% effective rate)	497.5		497.2
5.4% Senior Notes, due December 2042 ($400 million principal amount; 5.4% effective rate)	395.1		394.9
5.85% Senior Notes, due January 2044 ($400 million principal amount; 5.9% effective rate)	396.3		396.2
Total carrying value	2,510.3		2,680.2
Current portion (1)	—		126.8
Carrying value, less current portion	$	2,510.3	$	2,553.4
(1) Current portion of long-term debt at December 31, 2016, included the 5% Senior Notes due 2017, as well as the portion of 7.875% Senior Notes due 2019 and 4.875% Senior Notes due 2022 tendered in December 2016 but not settled until January 2017.

Schedule of maturities of long-term debt

The following is a summary of scheduled long-term debt maturities by year, as of December 31, 2017 (in millions):

2018	$	—
2019	201.4
2020	—
2021	—
2022	620.8
Thereafter	1,698.1
	$	2,520.3