Financial Instruments - Narrative (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2020 USD ($) interest_rate_swap	Dec. 31, 2019 USD ($)	Jun. 30, 2020 USD ($) interest_rate_swap	Jun. 30, 2019 USD ($)	Feb. 29, 2020 USD ($)
Derivative [Line Items]
Pretax net unrealized gain on derivatives maturing within next 12 months estimated to be reclassified from AOCI to sales			$ 9,000,000
Equity investments without readily determinable fair values	$ 487,000,000		487,000,000	$ 465,000,000
Unrealized gains recognized on investments in equity securities without readily determinable fair value			18,000,000	4,000,000
Unrealized losses recognized on investments in equity securities without readily determinable fair values			3,000,000	10,000,000
Cumulative unrealized gains on investments	127,000,000		127,000,000
Cumulative unrealized losses on investments	24,000,000		24,000,000
Payments of contingent consideration			106,000,000	$ 85,000,000
Fair value of loans payable and long-term debt, including current portion	34,500,000,000	$ 28,800,000,000	34,500,000,000
Debt, carrying amount	30,900,000,000	26,300,000,000	30,900,000,000
Accounts Receivable, Sale	1,900,000,000	2,700,000,000
Cash collateral received from counterparties	38,000,000	34,000,000	38,000,000
Cash collateral advanced to counterparties	0	0	0
Total swap notional amount	23,436,000,000	30,666,000,000	23,436,000,000
Face amount of debt	4,500,000,000		4,500,000,000
Level 2
Derivative [Line Items]
Cash equivalents	10,400,000,000	8,900,000,000	10,400,000,000
Derivatives Designated as Hedging Instruments
Derivative [Line Items]
Total swap notional amount	12,247,000,000	14,728,000,000	$ 12,247,000,000
Derivatives Designated as Hedging Instruments | Maximum
Derivative [Line Items]
Maximum average period of maturities of contracts in years (less than)			2 years
Derivatives Not Designated as Hedging Instruments
Derivative [Line Items]
Total swap notional amount	$ 11,189,000,000	$ 15,938,000,000	$ 11,189,000,000
Derivatives Not Designated as Hedging Instruments | Maximum
Derivative [Line Items]
Maximum average period of maturities of contracts in years (less than)			1 year
1.85% Notes Due 2020
Derivative [Line Items]
Face amount of debt					$ 1,250,000,000
Stated interest rate (as percent)					1.85%
Interest rate swap contracts
Derivative [Line Items]
Number of interest rate swaps held (in interest rate swaps)	14		14		5
Total swap notional amount					$ 250,000,000