Condensed Consolidated Statements of Income (Unaudited) - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Revenue
Commissions, fees and other	$ 2,736	$ 2,873	$ 8,378	$ 8,727
Fiduciary investment income	6	7	16	19
Total revenue	2,742	2,880	8,394	8,746
Expenses
Compensation and benefits	1,644	1,707	4,980	5,166
Other general expenses	685	756	2,283	2,249
Total operating expenses	2,329	2,463	7,263	7,415
Operating income	413	417	1,131	1,331
Interest income	3	3	10	7
Interest expense	(72)	(65)	(205)	(188)
Other income	8	35	51	34
Income before income taxes	352	390	987	1,184
Income taxes	49	75	155	220
Net income	303	315	832	964
Less: Net income attributable to noncontrolling interests	8	6	31	26
Net income attributable to Aon shareholders	$ 295	$ 309	$ 801	$ 938
Basic net income per share attributable to Aon shareholders	$ 1.05	$ 1.06	$ 2.83	$ 3.15
Diluted net income per share attributable to Aon shareholders	1.04	1.04	2.80	3.11
Cash dividends per share paid on ordinary shares	$ 0.30	$ 0.25	$ 0.85	$ 0.68
Weighted average ordinary shares outstanding - basic (in shares)	280.9	292.3	283.2	298.1
Weighted average ordinary shares outstanding - diluted (in shares)	283.8	296.1	285.9	301.6