Financial Instruments - Narrative (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2020 USD ($) interest_rate_swap	Dec. 31, 2019 USD ($)	Sep. 30, 2020 USD ($) interest_rate_swap	Sep. 30, 2019 USD ($)	Jun. 30, 2020 USD ($)	Feb. 29, 2020 USD ($) interest_rate_swap
Derivative [Line Items]
Pretax net unrealized losses on derivatives maturing within next 12 months estimated to be reclassified from AOCI to sales			$ 155,000,000
Equity investments without readily determinable fair values	$ 508,000,000		508,000,000	$ 393,000,000
Unrealized gains recognized on investments in equity securities without readily determinable fair value			21,000,000	4,000,000
Unrealized losses recognized on investments in equity securities without readily determinable fair values			3,000,000	12,000,000
Cumulative unrealized gains on investments	128,000,000		128,000,000
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	32,600,000,000	$ 28,800,000,000	32,600,000,000
Debt, carrying amount	28,700,000,000	26,300,000,000	28,700,000,000
Accounts Receivable, Sale	2,100,000,000	2,700,000,000
Cash collateral received from counterparties	0	34,000,000	0
Cash collateral advanced to counterparties	0	0	0
Total swap notional amount	27,151,000,000	30,666,000,000	27,151,000,000
Face amount of debt					$ 4,500,000,000
Level 2
Derivative [Line Items]
Cash equivalents	6,600,000,000	8,900,000,000	6,600,000,000
Derivatives Designated as Hedging Instruments
Derivative [Line Items]
Total swap notional amount	12,654,000,000	14,728,000,000	$ 12,654,000,000
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	$ 14,497,000,000	$ 15,938,000,000	$ 14,497,000,000
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) | interest_rate_swap	14		14			5
Total swap notional amount						$ 250,000,000