Revenue recognition - Cumulative effect of changes (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Jul. 01, 2018	Jun. 30, 2018
ASSETS
Trade accounts receivable, net	$ 2,065,158	$ 2,145,506	$ 2,145,517
Inventories	1,762,640	1,644,509	1,621,304
Prepaid expenses and other	165,213	149,461	134,886
Investments and other assets	757,795	803,069	801,049
LIABILITIES
Other accrued liabilities	549,791	530,621	502,333
Other liabilities	471,839	531,249	526,089
Deferred income taxes	265,418	236,418	234,858
EQUITY
Retained earnings	$ 11,902,300	11,630,756	11,625,975
Accounting Standards Update 2014-09
EQUITY
Retained earnings		$ 5,000
Calculated under Revenue Guidance in Effect before Topic 606
ASSETS
Trade accounts receivable, net			2,145,517
Inventories			1,621,304
Prepaid expenses and other			134,886
Investments and other assets			801,049
LIABILITIES
Other accrued liabilities			502,333
Other liabilities			526,089
Deferred income taxes			234,858
EQUITY
Retained earnings			11,625,975
Cumulative Effect of Adjustments | Accounting Standards Update 2014-09
ASSETS
Trade accounts receivable, net			(11)
Inventories			23,205
Prepaid expenses and other			14,575
Investments and other assets			2,020
LIABILITIES
Other accrued liabilities			28,288
Other liabilities			5,160
Deferred income taxes			1,560
EQUITY
Retained earnings			$ 4,781