Condensed Consolidated Statements of Income (Unaudited) - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2023	Sep. 30, 2022
Revenue
Total revenue	$ 2,953	$ 2,696	$ 10,001	$ 9,349
Expenses
Compensation and benefits	1,685	1,532	5,231	4,938
Information technology	135	133	403	371
Premises	74	71	217	216
Depreciation of fixed assets	42	37	119	115
Amortization and impairment of intangible assets	20	34	70	87
Other general expense	300	299	949	965
Accelerating Aon United Program expenses	6	0	6	0
Total operating expenses	2,262	2,106	6,995	6,692
Operating income	691	590	3,006	2,657
Interest income	9	7	19	15
Interest expense	(119)	(103)	(360)	(296)
Other income (expense)	(21)	16	(105)	71
Income before income taxes	560	510	2,560	2,447
Income tax expense	93	92	439	467
Net income	467	418	2,121	1,980
Less: Net income attributable to noncontrolling interests	11	10	55	48
Net income attributable to Aon shareholders	$ 456	$ 408	$ 2,066	$ 1,932
Basic net income per share attributable to Aon shareholders (in dollars per share)	$ 2.25	$ 1.93	$ 10.10	$ 9.06
Diluted net income per share attributable to Aon shareholders (in dollars per share)	$ 2.23	$ 1.92	$ 10.03	$ 9.00
Weighted average ordinary shares outstanding - basic (in shares)	202.9	210.9	204.6	213.2
Weighted average ordinary shares outstanding - diluted (in shares)	204.6	212.6	206.0	214.6