STOCKHOLDERS' EQUITY: - Repurchase (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	114 Months Ended
Jun. 30, 2017	Dec. 31, 2008
SCC share repurchase program:
Amount authorized for share repurchase program	$ 3,000.0	$ 500.0
Number of Shares Purchased	119.5
Cost of purchase of shares	$ 2.9
Closing price of NYSE (in dollars per share)	$ 34.63
Maximum number of shares that could purchased under the price @ $34.63	2.4
Percentage of ownership interest held by the parent company	88.90%

Equity impact of the cost of common and preferred stock that were repurchased during the period. Recorded using the cost method.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6928386&loc=d3e21463-112644

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 30
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6405813&loc=d3e23239-112655

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=27012166&loc=d3e187085-122770

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