CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2020	Mar. 31, 2019
Income Statement [Abstract]
Revenue	$ 47,417,639	$ 43,319,602	$ 95,282,381	$ 88,712,054
Cost of goods sold	46,029,532	41,894,846	92,663,060	85,989,718
Gross profit	1,388,107	1,424,756	2,619,321	2,722,336
Operating expenses:
Distribution, selling, and administrative	693,413	628,036	1,379,366	1,284,621
Depreciation	69,796	75,219	139,040	150,581
Amortization	23,999	48,547	59,270	95,685
Employee severance, litigation, and other	67,732	55,389	107,041	96,061
Impairment of PharMEDium assets	223,652	570,000	361,652	570,000
Operating income	309,515	47,565	572,952	525,388
Other (income) loss	(1,109)	(14,494)	1,733	(11,397)
Interest expense, net	34,421	43,275	65,428	85,445
Income before income taxes	276,203	18,784	505,791	451,340
Income tax (benefit) expense	(694,908)	(9,289)	(651,888)	31,514
Net income	971,111	28,073	1,157,679	419,826
Net (income) loss attributable to noncontrolling interest	(10,834)	(938)	(9,762)	961
Net income attributable to AmerisourceBergen Corporation	$ 960,277	$ 27,135	$ 1,147,917	$ 420,787
Earnings per share:
Basic (usd per share)	$ 4.68	$ 0.13	$ 5.58	$ 1.99
Diluted (usd per share)	$ 4.64	$ 0.13	$ 5.54	$ 1.97
Weighted average common shares outstanding:
Basic (shares)	205,370	210,934	205,693	211,503
Diluted (shares)	207,062	212,563	207,293	213,275
Cash dividends declared per share of common stock (usd per share)	$ 0.42	$ 0.40	$ 0.82	$ 0.80