Amount of long-term debt due after one year or the normal operating cycle, if longer, assumed at the acquisition date.

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Carrying value as of the balance sheet date of short-term borrowings using unsecured obligations issued by banks, corporations and other borrowers to investors. The maturities of these money market securities generally do not exceed 270 days.

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Face (par) amount of debt instrument at time of issuance.

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Contractual interest rate for funds borrowed, under the debt agreement.

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Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

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Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

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Amount of cash outflow for cost from early extinguishment and prepayment of debt. Includes, but is not limited to, third-party cost, premium paid, and other fee paid to lender directly for debt extinguishment or debt prepayment. Excludes accrued interest.

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The cash outflow during the period from the repayment of aggregate short-term and long-term debt. Excludes payment of capital lease obligations.

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Reflects the total carrying amount as of the balance sheet date of debt having initial terms less than one year or the normal operating cycle, if longer.

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Debt (Narrative) (Details)	1 Months Ended						3 Months Ended		9 Months Ended
Debt (Narrative) (Details)	Apr. 30, 2020 USD ($)	Mar. 31, 2020 USD ($)	Jan. 31, 2020 USD ($)	Sep. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)	Apr. 30, 2019 USD ($)	Sep. 30, 2020 USD ($)	Jun. 30, 2019 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	May 31, 2020 USD ($)	Apr. 01, 2019 USD ($)	Mar. 31, 2019 USD ($)	Mar. 31, 2019 EUR (€)	Jan. 31, 2019 USD ($)
Debt Instrument [Line Items]
Commercial paper outstanding							$ 0		$ 0
Payments for early extinguishment of debt									0	$ 585,000,000
April 2020 New Credit Facility
Debt Instrument [Line Items]
Debt facilities, maximum borrowing capacity	$ 1,000,000,000						$ 0		$ 0
Term of debt	1 year
2.250% Senior Debt Obligations Due 2030
Debt Instrument [Line Items]
Interest rate							2.25%		2.25%
1.349% Senior Debt Obligations Due 2026
Debt Instrument [Line Items]
Interest rate							1.349%		1.349%
1.979% Senior Debt Obligations Due 2030
Debt Instrument [Line Items]
Interest rate							1.979%		1.979%
Commercial Paper
Debt Instrument [Line Items]
Short-term debt							$ 1,500,000,000		$ 1,500,000,000
Jardine Lloyd Thompson Group plc
Debt Instrument [Line Items]
Repayments of debt					$ 553,000,000	$ 450,000,000
Debt assumed in acquisition												$ 1,000,000,000
Payments for early extinguishment of debt								$ 32,000,000
Revolving Credit Facility \| Amended Revolving Credit Facility
Debt Instrument [Line Items]
Debt facilities, maximum borrowing capacity							1,800,000,000		$ 1,800,000,000
Term of debt									5 years
Long-term line of credit		$ 1,000,000,000					0		$ 0
Term Loan Facility \| $500 Million One-Year Term Loan Facility
Debt Instrument [Line Items]
Debt facilities, maximum borrowing capacity			$ 500,000,000
Term of debt			1 year
Long-term line of credit							0		0
Repayments of debt							500,000,000
Term Loan Facility \| $500 Million Two-Year Term Loan Facility
Debt Instrument [Line Items]
Debt facilities, maximum borrowing capacity			$ 500,000,000
Term of debt			2 years
Long-term line of credit							500,000,000		500,000,000
Senior Notes
Debt Instrument [Line Items]
Repayments of debt		$ 500,000,000		$ 300,000,000
Debt instrument face amount															$ 5,000,000,000
Senior Notes \| 2.250% Senior Debt Obligations Due 2030
Debt Instrument [Line Items]
Debt instrument face amount											$ 750,000,000
Interest rate											2.25%
Senior Notes \| 1.349% Senior Debt Obligations Due 2026
Debt Instrument [Line Items]
Debt instrument face amount \| €														€ 550,000,000
Interest rate													1.349%	1.349%
Senior Notes \| 1.979% Senior Debt Obligations Due 2030
Debt Instrument [Line Items]
Debt instrument face amount \| €														€ 550,000,000
Interest rate													1.979%	1.979%
Senior Notes \| Senior Debt Obligations 4.375% Due 2029
Debt Instrument [Line Items]
Debt instrument face amount							$ 1,500,000,000		$ 1,500,000,000				$ 250,000,000		1,250,000,000
Interest rate							4.375%		4.375%
Senior Notes \| Senior Debt Obligations 3.50% Due 2020
Debt Instrument [Line Items]
Debt instrument face amount															$ 700,000,000
Interest rate															3.50%
Senior Notes \| Senior Debt Obligations 3.875% Due 2024
Debt Instrument [Line Items]
Debt instrument face amount															$ 1,000,000,000
Interest rate															3.875%
Senior Notes \| Senior Debt Obligations 4.75% Due 2039
Debt Instrument [Line Items]
Debt instrument face amount															$ 500,000,000
Interest rate															4.75%
Senior Notes \| Senior Debt Obligations 4.90% Due 2049
Debt Instrument [Line Items]
Debt instrument face amount															$ 1,250,000,000
Interest rate															4.90%
Senior Notes \| Floating Rate Senior Notes Due 2021
Debt Instrument [Line Items]
Debt instrument face amount															$ 300,000,000
Senior Notes \| Jardine Lloyd Thompson Group plc
Debt Instrument [Line Items]
Debt instrument face amount \| €														€ 1,100,000,000