Financial Instruments (Derivative Notional Amounts) (Details) - USD ($) $ in Billions	Mar. 31, 2020	Dec. 31, 2019
Foreign exchange contracts | Derivatives Designated as Hedging Instruments: | Cash flow hedges
Derivative Instruments, Gain (Loss) [Line Items]
Derivative notional amount	$ 12.6	$ 13.2
Foreign exchange contracts | Derivatives Designated as Hedging Instruments: | Fair value hedges
Derivative Instruments, Gain (Loss) [Line Items]
Derivative notional amount	0.5	0.5
Foreign exchange contracts | Derivatives Designated as Hedging Instruments: | Net investment hedges
Derivative Instruments, Gain (Loss) [Line Items]
Derivative notional amount	9.3	9.3
Foreign exchange contracts | Derivatives Not Designated as Hedging Instruments:
Derivative Instruments, Gain (Loss) [Line Items]
Derivative notional amount	30.9	43.5
Other contracts | Derivatives Not Designated as Hedging Instruments:
Derivative Instruments, Gain (Loss) [Line Items]
Derivative notional amount	$ 1.1	$ 0.1