Entity Tax Identification Number Entity Tax Identification Number Entity File Number Entity File Number Cover [Abstract] Title of 12(b) Security Title of 12(b) Security Guarantees of Aon plc’s 4.750% Senior Notes due 2045 Senior Notes due 2045 [Member] Senior Notes due 2045 Guarantees of Aon North America, Inc.'s 5.125% Senior Notes due 2027 Guarantees Of Aon North America, Inc.’s 5.125% Senior Notes Due 2027 [Member] Guarantees Of Aon North America, Inc.’s 5.125% Senior Notes Due 2027 Local Phone Number Local Phone Number Class of Stock [Domain] Class of Stock [Domain] Guarantees of Aon Corporation and Aon Global Holdings plc’s 2.900% Senior Notes due 2051 Senior Notes due 2051 [Member] Senior Notes due 2051 Soliciting Material Soliciting Material Entity Address, Address Line One Entity Address, Address Line One Entity Address, Postal Zip Code Entity Address, Postal Zip Code Entity Registrant Name Entity Registrant Name Entity Incorporation, State or Country Code Entity Incorporation, State or Country Code Guarantees of Aon Corporation and Aon Global Holdings plc’s 5.000% Senior Notes due 2032 Guarantees Of Aon Plc’s 5.00% Senior Notes Due 2032 [Member] Guarantees Of Aon Plc’s 5.00% Senior Notes Due 2032 [Member] Written Communications Written Communications Guarantees of Aon Corporation and Aon Global Holdings plc’s 2.050% Senior Notes due 2031 Senior Notes due 2031 [Member] Senior Notes due 2031 Guarantees of Aon North America, Inc.'s 5.150% Senior Notes due 2029 Guarantees of Aon North America, Inc.'s 5.150% Senior Notes due 2029 [Member] Guarantees of Aon North America, Inc.'s 5.150% Senior Notes due 2029 Trading Symbol Trading Symbol Guarantees of Aon North America, Inc.'s 5.300% Senior Notes due 2031 Guarantees of Aon North America, Inc.'s 5.300% Senior Notes due 2031 [Member] Guarantees of Aon North America, Inc.'s 5.300% Senior Notes due 2031 Guarantees of Aon Corporation and Aon Global Holdings plc’s 2.600% Senior Notes due 2031 Guarantees Of Aon Plc’s 2.60% Senior Notes Due 2031 [Member] Guarantees Of Aon Plc’s 2.60% Senior Notes Due 2031 City Area Code City Area Code Guarantees of Aon plc’s 4.450% Senior Notes due 2043 Senior Notes due 2043 [Member] Senior Notes due 2043 Document Information [Table] Document Information [Table] Guarantees of Aon plc’s 4.600% Senior Notes due 2044 Senior Notes due 2044 [Member] Senior Notes due 2044 Guarantees of Aon Corporation and Aon Global Holdings plc's 5.350% Senior Notes due 2033 Guarantees Of Aon Corporation And Aon Global Holdings plc's 5.35% Senior Notes Due 2033 [Member] Guarantees Of Aon Corporation And Aon Global Holdings plc's 5.35% Senior Notes Due 2033 Document Period End Date Document Period End Date Amendment Flag Amendment Flag Pre-commencement Issuer Tender Offer Pre-commencement Issuer Tender Offer Entity Address, City or Town Entity Address, City or Town Entity Address, Country Entity Address, Country Class A Ordinary Shares $0.01 nominal value Capital Unit, Class A [Member] Security Exchange Name Security Exchange Name Guarantees of Aon Corporation and Aon Global Holdings plc’s 2.850% Senior Notes due 2027 Guarantees of Aon Corporation and Aon Global Holdings plc’s 2.85% Senior Notes due 2027 [Member] Guarantees of Aon Corporation and Aon Global Holdings plc’s 2.85% Senior Notes due 2027 Guarantees of Aon North America, Inc.'s 5.450% Senior Notes due 2034 Guarantees of Aon North America, Inc.'s 5.450% Senior Notes due 2034 [Member] Guarantees of Aon North America, Inc.'s 5.450% Senior Notes due 2034 Guarantees of Aon Corporation and Aon Global Holdings plc’s 3.900% Senior Notes due 2052 Guarantees of Aon Corporation and Aon Global Holdings plc’s 3.90% Senior Notes due 2052 [Member] Guarantees of Aon Corporation and Aon Global Holdings plc’s 3.90% Senior Notes due 2052 Document Information [Line Items] Document Information [Line Items] Guarantees of Aon plc’s 4.250% Senior Notes due 2042 Senior Notes due 2042 [Member] Senior Notes due 2042 Document Type Document Type Class of Stock [Axis] Class of Stock [Axis] Pre-commencement Tender Offer Pre-commencement Tender Offer Entity Central Index Key Entity Central Index Key Entity Emerging Growth Company Entity Emerging Growth Company Guarantees of Aon North America, Inc.'s 5.750% Senior Notes due 2054 Guarantees of Aon North America, Inc.'s 5.750% Senior Notes due 2054 [Member] Guarantees of Aon North America, Inc.'s 5.750% Senior Notes due 2054