CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2018
Statement of Comprehensive Income [Abstract]
Net (loss) income	$ (3,399,558)	$ 854,135	$ 1,615,892
Other comprehensive (loss) income:
Foreign currency translation adjustments	(7,872)	(32,957)	(36,904)
Loss on consolidation of equity investments	0	0	45,941
Other, net	(1,074)	(271)	(756)
Total other comprehensive (loss) income	(8,946)	(33,228)	8,281
Total comprehensive (loss) income	(3,408,504)	820,907	1,624,173
Comprehensive loss attributable to noncontrolling interest	2,923	1,746	50,829
Comprehensive (loss) income attributable to AmerisourceBergen Corporation	$ (3,405,581)	$ 822,653	$ 1,675,002