Debt	3 Months Ended
Mar. 31, 2016
Debt Disclosure [Abstract]
Debt	Debt Revolving Credit Facilities As of March 31, 2016, Aon plc had two primary committed credit facilities outstanding: its $400 million U.S. credit facility expiring in March 2017 (the "2017 Facility") and its $900 million multi-currency U.S. credit facility originally expiring in February 2020. Effective February 2, 2016, the $900 million multi-currency U.S. credit facility terms were extended for one year and will now expire on February 2, 2021 (the "2021 Facility"). Each of these facilities included customary representations, warranties and covenants, including financial covenants that require Aon plc to maintain specified ratios of adjusted consolidated EBITDA to consolidated interest expense and consolidated debt to adjusted consolidated EBITDA, in each case, tested quarterly. At March 31, 2016, Aon plc did not have borrowings under either the 2017 Facility or the 2021 Facility, and was in compliance with all covenants contained therein during the three months ended March 31, 2016. Commercial Paper Aon Corporation, a wholly-owned subsidiary of Aon plc, has established a U.S. commercial paper program, which provides for commercial paper to be issued in an aggregate principal amount of up to $900 million, and Aon plc has established a European multi-currency commercial paper program that provides for commercial paper to be issued in an aggregate principal amount of up to €300 million. The U.S. commercial paper program is fully and unconditionally guaranteed by Aon plc and the European commercial paper program is fully and unconditionally guaranteed by Aon Corporation. In the aggregate, the Company had $184 million and $50 million of commercial paper outstanding at March 31, 2016 and December 31, 2015, respectively, which was included in Short-term debt and current portion of long-term debt in the Company's Condensed Consolidated Statements of Financial Position. The weighted average commercial paper outstanding for the three months ended March 31, 2016 was $177 million. The weighted average interest rate of the commercial paper outstanding for the three months ended March 31, 2016 was 0.11%. Notes On March 1, 2016, Aon plc issued $750 million of 3.875% Senior Notes due December 2025. The Company used the proceeds of the issuance for general corporate purposes.

Debt

Revolving Credit Facilities

As of March 31, 2016, Aon plc had two primary committed credit facilities outstanding: its $400 million U.S. credit facility expiring in March 2017 (the "2017 Facility") and its $900 million multi-currency U.S. credit facility originally expiring in February 2020. Effective February 2, 2016, the $900 million multi-currency U.S. credit facility terms were extended for one year and will now expire on February 2, 2021 (the "2021 Facility").

Each of these facilities included customary representations, warranties and covenants, including financial covenants that require Aon plc to maintain specified ratios of adjusted consolidated EBITDA to consolidated interest expense and consolidated debt to adjusted consolidated EBITDA, in each case, tested quarterly. At March 31, 2016, Aon plc did not have borrowings under either the 2017 Facility or the 2021 Facility, and was in compliance with all covenants contained therein during the three months ended March 31, 2016.

Commercial Paper

Aon Corporation, a wholly-owned subsidiary of Aon plc, has established a U.S. commercial paper program, which provides for commercial paper to be issued in an aggregate principal amount of up to $900 million, and Aon plc has established a European multi-currency commercial paper program that provides for commercial paper to be issued in an aggregate principal amount of up to €300 million. The U.S. commercial paper program is fully and unconditionally guaranteed by Aon plc and the European commercial paper program is fully and unconditionally guaranteed by Aon Corporation. In the aggregate, the Company had $184 million and $50 million of commercial paper outstanding at March 31, 2016 and December 31, 2015, respectively, which was included in Short-term debt and current portion of long-term debt in the Company's Condensed Consolidated Statements of Financial Position. The weighted average commercial paper outstanding for the three months ended March 31, 2016 was $177 million. The weighted average interest rate of the commercial paper outstanding for the three months ended March 31, 2016 was 0.11%.

Notes

On March 1, 2016, Aon plc issued $750 million of 3.875% Senior Notes due December 2025. The Company used the proceeds of the issuance for general corporate purposes.