Fair Value Measurements - Additional Information (Detail)	1 Months Ended	3 Months Ended
	Apr. 27, 2021 USD ($)	Mar. 31, 2021 USD ($)	Mar. 31, 2020 USD ($)	Mar. 31, 2021 EUR (€)	Dec. 31, 2020 USD ($)	Dec. 31, 2020 EUR (€)
Derivatives, Fair Value [Line Items]
Carrying amount of our investments without readily determinable fair values		$ 404,000,000			$ 402,000,000
Investments without readily determinable fair values, impairment loss		0
Cumulative adjustments due to observable price changes		87,000,000
Unrealized gain (loss) on cash flow hedges		909,000,000	$ (2,210,000,000)
Derivative asset fair value of collateral					(200,000,000)
Interest rate swaps
Derivatives, Fair Value [Line Items]
Net investment hedge		17,852,000,000			17,768,000,000
Interest rate swaps | Fair Value Hedges
Derivatives, Fair Value [Line Items]
Notional amount of derivative instruments entered during period		1,000,000,000.0	2,400,000,000
Notional amount of derivative settled during period		895,000,000	1,500,000,000
Ineffectiveness portion of interest rate swaps			60,000,000
Interest rate swaps | Fair Value Hedges | Subsequent Event
Derivatives, Fair Value [Line Items]
Notional amount of derivative instruments entered during period	$ 675,000,000
Cross currency swaps
Derivatives, Fair Value [Line Items]
Net investment hedge		32,502,000,000			26,288,000,000
Cross currency swaps | Cash Flow Hedging
Derivatives, Fair Value [Line Items]
Notional amount of derivative instruments entered during period		6,200,000,000	0
Notional amount of derivative settled during period		0	0
Pre-tax gains (loss) recognized in other comprehensive income (loss)		(226,000,000)	(3,000,000,000.0)
Forward starting interest rate swaps
Derivatives, Fair Value [Line Items]
Net investment hedge		1,000,000,000			2,000,000,000
Forward starting interest rate swaps | Cash Flow Hedging
Derivatives, Fair Value [Line Items]
Notional amount of derivative instruments entered during period		0	0
Notional amount of derivative settled during period		1,000,000,000.0	1,000,000,000.0
Payments for settlement of derivative		237,000,000	293,000,000
Pre-tax gains (loss) recognized in other comprehensive income (loss)		400,000,000	(840,000,000)
Treasury rate locks | Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Notional amount of derivative instruments entered during period		0	1,600,000,000
Notional amount of derivative settled during period		0	1,600,000,000
Pre-tax gains (loss) recognized in other comprehensive income (loss)		0
Treasury rate locks | Cash Flow Hedging
Derivatives, Fair Value [Line Items]
Notional amount of derivative instruments entered during period		4,700,000,000	500,000,000
Notional amount of derivative settled during period		4,700,000,000	500,000,000
Proceeds from settlement of derivative		251,000,000
Unrealized gain (loss) on cash flow hedges		251,000,000
Euro Denominated Debt | Net Investment Hedges
Derivatives, Fair Value [Line Items]
Net investment hedge | €				€ 750,000,000		€ 750,000,000
Foreign exchange forwards
Derivatives, Fair Value [Line Items]
Net investment hedge		1,300,000,000			$ 1,405,000,000
Foreign exchange forwards | Not Designated as Hedging Instrument
Derivatives, Fair Value [Line Items]
Notional amount of derivative instruments entered during period		3,500,000,000	2,700,000,000
Notional amount of derivative settled during period		$ 3,600,000,000	$ 2,800,000,000