Revenue recognition - Revenue by geographic region (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2020	Mar. 31, 2019
Disaggregation of Revenue [Line Items]
Revenues from contracts	$ 3,702,432	$ 3,687,518	$ 10,534,917	$ 10,638,857
North America
Disaggregation of Revenue [Line Items]
Revenues from contracts	2,507,566	2,398,975	7,107,655	6,893,872
Europe
Disaggregation of Revenue [Line Items]
Revenues from contracts	726,577	786,123	2,018,301	2,226,983
Asia Pacific
Disaggregation of Revenue [Line Items]
Revenues from contracts	430,500	458,122	1,292,054	1,385,736
Latin America
Disaggregation of Revenue [Line Items]
Revenues from contracts	$ 37,789	$ 44,298	$ 116,907	$ 132,266