XML 64 R52.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Cash and Cash Equivalents and Short-term Investments (Details) £ in Millions, $ in Millions | 9 Months Ended |  |
--- | --- | --- | ---
Sep. 30, 2018 USD ($) | Sep. 30, 2018 GBP (£) | Sep. 30, 2018 USD ($) | Dec. 31, 2017 GBP (£) | Dec. 31, 2017 USD ($)
Cash, Cash Equivalents, and Short-term Investments [Abstract] |  |  |  |  |
Cash and cash equivalents and short-term investments |  |  | $ 651.0 |  | $ 1,285.0
Cash and cash equivalents and short term investments, period increase (decrease) | $ (634.0) |  |  |  |
Restricted cash |  |  | 97.0 |  | 96.0
Operating funds in U.K. |  | £ 42.8 | $ 56.4 | £ 42.7 | $ 57.1

X
- Definition Cash And Cash Equivalents And Short Term Investments, Period Increase (Decrease) + References No definition available. + Details
Name: | aon_CashAndCashEquivalentsAndShortTermInvestmentsPeriodIncreaseDecrease
Namespace Prefix: | aon_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Cash and Cash Equivalents and Short-Term Investments + References No definition available. + Details
Name: | aon_CashandCashEquivalentsandShortTermInvestments
Namespace Prefix: | aon_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Represents cash that is restricted for minimum operating fund requirements. + References No definition available. + Details
Name: | aon_RestrictedCashOperatingFunds
Namespace Prefix: | aon_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- References No definition available. + Details
Name: | us-gaap_CashCashEquivalentsAndShortTermInvestmentsAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The current cash, cash equivalents and investments that are restricted as to withdrawal or usage. Restrictions may include legally restricted deposits held as compensating balances against short-term borrowing arrangements, contracts entered into with others, or entity statements of intention with regard to particular deposits; however, time deposits and short-term certificates of deposit are not generally included in legally restricted deposits. Excludes compensating balance arrangements that are not agreements which legally restrict the use of cash amounts shown on the balance sheet. Includes current cash equivalents and investments that are similarly restricted as to withdrawal, usage or disposal. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.1) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_RestrictedCashAndInvestmentsCurrent
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant