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OTHER DISCLOSURES. (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Expense recognized for defined contribution retirement plans	$ 89.4	$ 80.7	$ 74.9
Senior officers [Member] | Supplemental Savings Plan [Member]
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Supplemental Savings Plan, minimum deferral period	2 years
Supplemental Savings Plan, maximum deferral period	15 years
Amount of cash incentive compensation senior officers elected to defer	$ 95.5	$ 83.4	$ 72.8
Maximum [Member] | Senior officers [Member] | Supplemental Savings Plan [Member]
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Deferral percentage of cash incentive compensation	100.00%

X

- Definition

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+ References

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- Definition

Deferred Compensation Arrangement with Individual, Initial Maximum Contractual Term

+ References

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- Definition

Deferred Compensation Arrangement with Individual, Initial Minimum Contractual Term

+ References

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- Definition

Amount of commitment made to pay deferred cash remuneration.

+ References

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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- Definition

Amount of cost for defined contribution plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 70
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=49170846&loc=d3e28014-114942

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