Consolidated Statements of Income - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Revenue
Total revenue	$ 12,193	$ 11,066	$ 11,013
Expenses
Compensation and benefits	6,738	5,905	6,054
Information technology	477	444	494
Premises	327	291	339
Depreciation of fixed assets	179	167	172
Amortization and impairment of intangible assets	147	246	392
Other general expense	2,235	1,232	1,393
Total operating expenses	10,103	8,285	8,844
Operating income	2,090	2,781	2,169
Interest income	11	6	8
Interest expense	(322)	(334)	(307)
Other income	152	13	0
Income before income taxes	1,931	2,466	1,870
Income tax expense	623	448	297
Net income	1,308	2,018	1,573
Less: Net income attributable to noncontrolling interests	53	49	41
Net income attributable to Aon shareholders	$ 1,255	$ 1,969	$ 1,532
Basic net income per share attributable to Aon shareholders (in dollars per share)	$ 5.59	$ 8.49	$ 6.42
Diluted net income per share attributable to Aon shareholders (in dollars per share)	$ 5.55	$ 8.45	$ 6.37
Weighted average ordinary shares outstanding - basic (in shares)	224.7	231.9	238.6
Weighted average ordinary shares outstanding - diluted (in shares)	226.1	233.1	240.6