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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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Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

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

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Nominal or face amount used to calculate payments on the derivative asset.

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Amount of the cost of borrowed funds accounted for as interest expense for debt.

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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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The cash outflow paid to third parties in connection with debt origination, which will be amortized over the remaining maturity period of the associated long-term debt.

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Debt (Narrative) (Details) £ in Billions	1 Months Ended	3 Months Ended	12 Months Ended
Debt (Narrative) (Details) £ in Billions	Mar. 31, 2019 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Mar. 31, 2019 EUR (€)	Jan. 31, 2019 USD ($)	Oct. 01, 2018 USD ($)	Sep. 30, 2018 USD ($)	Sep. 18, 2018 GBP (£)	Mar. 31, 2018 USD ($)
Debt Instrument [Line Items]
Commercial paper outstanding	$ 748,000,000	$ 748,000,000	$ 0
1.349% Senior Debt Obligations Due 2026
Debt Instrument [Line Items]
Interest rate	1.349%	1.349%		1.349%
1.979% Senior Debt Obligations Due 2030
Debt Instrument [Line Items]
Interest rate	1.979%	1.979%		1.979%
Loan Facility One
Debt Instrument [Line Items]
Debt facilities, maximum borrowing capacity	$ 300,000,000	$ 300,000,000
Loan Facility Two
Debt Instrument [Line Items]
Revolving credit facility, amount outstanding	$ 300,000,000	$ 300,000,000
4.20% Senior Debt Obligations Due 2048
Debt Instrument [Line Items]
Proceeds from issuance of debt									$ 600,000,000
Interest rate	4.20%	4.20%		4.20%					4.20%
Commercial Paper
Debt Instrument [Line Items]
Debt financing program	$ 1,500,000,000	$ 1,500,000,000
Effective interest rate	2.78%	2.78%		2.78%
Jardine Lloyd Thompson Group plc \| Bridge Loan
Debt Instrument [Line Items]
Derivative, notional amount	$ 0	$ 0						£ 5.2
Payments of debt issuance costs			35,000,000
Amortization of debt issuance costs			$ 30,000,000
Interest expense, debt		5,000,000
Senior Notes
Debt Instrument [Line Items]
Proceeds from issuance of debt					$ 5,000,000,000
Senior Notes \| Senior Debt Obligations 3.50% Due 2020
Debt Instrument [Line Items]
Proceeds from issuance of debt					$ 700,000,000
Interest rate					3.50%
Senior Notes \| Senior Debt Obligations 3.875% Due 2024
Debt Instrument [Line Items]
Proceeds from issuance of debt					$ 1,000,000,000
Interest rate					3.875%
Senior Notes \| Senior Debt Obligations 4.375% Due 2029
Debt Instrument [Line Items]
Proceeds from issuance of debt	$ 1,500,000,000.0	$ 1,500,000,000.0			$ 1,250,000,000.00
Interest rate					4.375%
Senior Notes \| Senior Debt Obligations 4.75% Due 2039
Debt Instrument [Line Items]
Proceeds from issuance of debt					$ 500,000,000
Interest rate					4.75%
Senior Notes \| Senior Debt Obligations 4.90% Due 2049
Debt Instrument [Line Items]
Proceeds from issuance of debt					$ 1,250,000,000.00
Interest rate					4.90%
Senior Notes \| Floating Rate Senior Notes Due 2021
Debt Instrument [Line Items]
Proceeds from issuance of debt					$ 300,000,000
Senior Notes \| 1.349% Senior Debt Obligations Due 2026
Debt Instrument [Line Items]
Proceeds from issuance of debt \| €				€ 550,000,000
Interest rate	1.349%	1.349%		1.349%
Senior Notes \| 1.979% Senior Debt Obligations Due 2030
Debt Instrument [Line Items]
Proceeds from issuance of debt \| €				€ 550,000,000
Interest rate	1.979%	1.979%		1.979%
Senior Notes \| Senior Debt Obligations 4.375% Due 2019
Debt Instrument [Line Items]
Proceeds from issuance of debt	$ 250,000,000	$ 250,000,000
Senior Notes \| Jardine Lloyd Thompson Group plc
Debt Instrument [Line Items]
Proceeds from issuance of debt \| €				€ 1,100,000,000
Term Loan Facility \| Loan Facility One
Debt Instrument [Line Items]
Term of debt	1 year
Term Loan Facility \| Loan Facility Two
Debt Instrument [Line Items]
Term of debt	3 years
Term Loan Facility \| Loan Facilities Closed March 2019
Debt Instrument [Line Items]
Revolving credit facility, amount outstanding	$ 0	0
Revolving Credit Facility \| Amended Revolving Credit Facility March 27, 2014
Debt Instrument [Line Items]
Revolving credit facility, amount outstanding	$ 0	$ 0
Term of debt		5 years
Debt facilities, maximum borrowing capacity						$ 1,800,000,000	$ 1,500,000,000.0