Consolidated Statements of Income - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Revenue
Total revenue	$ 13,376	$ 12,479	$ 12,193
Expenses
Compensation and benefits	6,902	6,477	6,738
Information technology	534	509	477
Premises	294	289	327
Depreciation of fixed assets	167	151	179
Amortization and impairment of intangible assets	89	113	147
Other general expense	1,470	1,271	2,235
Accelerating Aon United Program expenses	135	0	0
Total operating expenses	9,591	8,810	10,103
Operating income	3,785	3,669	2,090
Interest income	31	18	11
Interest expense	(484)	(406)	(322)
Other income (expense)	(163)	(125)	152
Income before income taxes	3,169	3,156	1,931
Income tax expense	541	510	623
Net income	2,628	2,646	1,308
Less: Net income attributable to noncontrolling interests	64	57	53
Net income attributable to Aon shareholders	$ 2,564	$ 2,589	$ 1,255
Basic net income per share attributable to Aon shareholders (in dollars per share)	$ 12.60	$ 12.23	$ 5.59
Diluted net income per share attributable to Aon shareholders (in dollars per share)	$ 12.51	$ 12.14	$ 5.55
Weighted average ordinary shares outstanding - basic (in shares)	203.5	211.7	224.7
Weighted average ordinary shares outstanding - diluted (in shares)	205.0	213.2	226.1