Condensed Consolidated Statements of Income (Unaudited) - USD ($) shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Revenue
Commissions, fees and other	$ 2,761	$ 2,800	$ 5,548	$ 5,642
Fiduciary investment income	5	5	10	10
Total revenue	2,766	2,805	5,558	5,652
Expenses
Compensation and benefits	1,688	1,653	3,337	3,336
Other general expenses	673	875	1,366	1,598
Total operating expenses	2,361	2,528	4,703	4,934
Operating income	405	277	855	718
Interest income	3	4	5	7
Interest expense	(73)	(68)	(142)	(133)
Other income	0	1	18	43
Income before income taxes	335	214	736	635
Income taxes	55	26	129	106
Net income	280	188	607	529
Less: Net income attributable to noncontrolling interests	8	10	20	23
Net income attributable to Aon shareholders	$ 272	$ 178	$ 587	$ 506
Basic net income per share attributable to Aon shareholders (in dollars per share)	$ 1.01	$ 0.63	$ 2.17	$ 1.78
Diluted net income per share attributable to Aon shareholders (in dollars per share)	1.01	0.62	2.16	1.76
Cash dividends per share paid on ordinary shares (in dollars per share)	$ 0.328	$ 0.3	$ 0.63	$ 0.55
Weighted average ordinary shares outstanding - basic (in shares)	268.0	284.5	269.9	284.3
Weighted average ordinary shares outstanding - diluted (in shares)	269.8	286.7	271.7	286.9