Condensed Consolidated Statements of Income (Unaudited) - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Revenue
Total revenue	$ 3,525	$ 3,219
Expenses
Compensation and benefits	1,719	1,522
Information technology	114	111
Premises	77	73
Depreciation of fixed assets	41	41
Amortization of intangible assets	40	97
Other general expense	289	342
Total operating expenses	2,280	2,186
Operating income	1,245	1,033
Interest income	3	2
Interest expense	(79)	(83)
Other income (expense)	(2)	28
Income before income taxes	1,167	980
Income tax expense	234	189
Net income	933	791
Less: Net income attributable to noncontrolling interests	20	19
Net income attributable to Aon shareholders	$ 913	$ 772
Basic net income per share attributable to Aon shareholders (in dollars per share)	$ 4.02	$ 3.31
Diluted net income per share attributable to Aon shareholders (in dollars per share)	$ 4.00	$ 3.29
Weighted average ordinary shares outstanding - basic (in shares)	227.1	233.2
Weighted average ordinary shares outstanding - diluted (in shares)	228.1	234.5