STOCKHOLDERS' EQUITY: (Details 2) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended							3 Months Ended			12 Months Ended		60 Months Ended	93 Months Ended
	Sep. 30, 2015	Aug. 31, 2015	Jul. 31, 2015	Apr. 30, 2015	Mar. 31, 2015	Feb. 28, 2015	Jan. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Sep. 30, 2015	Dec. 31, 2008
SCC share repurchase program:
Amount authorized for share repurchase program	$ 3,000.0							$ 3,000.0						$ 3,000.0	$ 500.0
Total Number of Shares Purchased	3,724,273	6,160,000	1,603,800	1,511,200	4,563,649	2,590,076	5,927,154	11,488,073	1,511,200	13,080,879	22,711,428	10,245,000	46,914,486	105,951,066
Average Price Paid per Share (in dollars per share)	$ 26.69	$ 26.90	$ 27.84	$ 29.42	$ 29.16	$ 29.45	$ 27.12	$ 26.97	$ 29.42	$ 29.29	$ 30.06	$ 27.47	$ 18.72	$ 24.22
Total Number of Shares Purchased as Part of Publicly Announced Plan	105,951,066	102,226,793	96,066,793	94,462,993	92,951,793	88,388,144	85,798,068	105,951,066		92,951,793	79,870,914	57,159,486	46,914,486	105,951,066
Maximum Number of Shares that May Yet Be Purchased Under the Plan @ $26.72	16,219,324							16,219,324						16,219,324
Total Cost	$ 99.4	$ 165.7	$ 44.6	$ 44.5	$ 133.1	$ 76.3	$ 160.7	$ 309.7	$ 44.5	$ 370.1	$ 682.8	$ 281.4	$ 878.1	$ 2,566.6
Percentage of ownership interest held by the parent company	87.40%							87.40%						87.40%