INCOME TAXES: - Provision (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
U.S. federal and state:
Deferred	$ 686.2	$ (109.4)	$ (143.0)
Uncertain tax positions	16.2	20.3	80.0
Provision for income taxes	702.4	(89.1)	(63.0)
Foreign (Peru and Mexico):
Current	951.7	625.0	620.4
Deferred	(60.7)	(34.8)	(92.5)
Provision for income taxes	891.0	590.2	527.9
Total provision for income taxes	1,593.4	501.1	464.9
Earnings by location:
U.S.	(1.5)	(1.9)	(2.1)
Peru	284.6	(85.7)	213.2
Mexico	2,019.6	1,343.6	978.1
Foreign	2,304.2	1,257.9	1,191.3
Income before income taxes	$ 2,302.7	$ 1,256.0	$ 1,189.2

The component of total income tax expense for the period comprised of the increase (decrease) during the period in the entity's domestic and state deferred tax assets and liabilities attributable to continuing operations as determined by applying the provisions of the federally enacted and applicable state tax law.

No definition available.