Fair Value Measurements - Schedule of Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Assets:
Total	$ 2,664	$ 1,226
Other liabilities:
Total	2,680	1,689
Foreign exchange forwards | Prepaid expenses and other
Assets:
Derivative asset	2
Foreign exchange forwards | Other assets
Assets:
Derivative asset		5
Fixed income securities | Other assets
Assets:
Debt securities, available-for-sale	462	442
Interest rate swaps | Prepaid expenses and other
Assets:
Derivative asset	28
Interest rate swaps | Other assets
Assets:
Derivative asset	1,768	568
Interest rate swaps | Other liabilities
Other liabilities:
Derivative liabilities	317	173
Cross currency swaps | Other assets
Assets:
Derivative asset	404	211
Cross currency swaps | Other liabilities
Other liabilities:
Derivative liabilities	1,383	912
Forward starting interest rate swaps | Other current liabilities
Other liabilities:
Derivative liabilities	499
Forward starting interest rate swaps | Other liabilities
Other liabilities:
Derivative liabilities	481	604
Level 1
Assets:
Total	0	0
Other liabilities:
Total	0	0
Level 1 | Foreign exchange forwards | Prepaid expenses and other
Assets:
Derivative asset	0
Level 1 | Foreign exchange forwards | Other assets
Assets:
Derivative asset		0
Level 1 | Fixed income securities | Other assets
Assets:
Debt securities, available-for-sale	0	0
Level 1 | Interest rate swaps | Prepaid expenses and other
Assets:
Derivative asset	0
Level 1 | Interest rate swaps | Other assets
Assets:
Derivative asset	0	0
Level 1 | Interest rate swaps | Other liabilities
Other liabilities:
Derivative liabilities	0	0
Level 1 | Cross currency swaps | Other assets
Assets:
Derivative asset	0	0
Level 1 | Cross currency swaps | Other liabilities
Other liabilities:
Derivative liabilities	0	0
Level 1 | Forward starting interest rate swaps | Other current liabilities
Other liabilities:
Derivative liabilities	0
Level 1 | Forward starting interest rate swaps | Other liabilities
Other liabilities:
Derivative liabilities	0	0
Level 2
Assets:
Total	2,664	1,226
Other liabilities:
Total	2,680	1,689
Level 2 | Foreign exchange forwards | Prepaid expenses and other
Assets:
Derivative asset	2
Level 2 | Foreign exchange forwards | Other assets
Assets:
Derivative asset		5
Level 2 | Fixed income securities | Other assets
Assets:
Debt securities, available-for-sale	462	442
Level 2 | Interest rate swaps | Prepaid expenses and other
Assets:
Derivative asset	28
Level 2 | Interest rate swaps | Other assets
Assets:
Derivative asset	1,768	568
Level 2 | Interest rate swaps | Other liabilities
Other liabilities:
Derivative liabilities	317	173
Level 2 | Cross currency swaps | Other assets
Assets:
Derivative asset	404	211
Level 2 | Cross currency swaps | Other liabilities
Other liabilities:
Derivative liabilities	1,383	912
Level 2 | Forward starting interest rate swaps | Other current liabilities
Other liabilities:
Derivative liabilities	499
Level 2 | Forward starting interest rate swaps | Other liabilities
Other liabilities:
Derivative liabilities	481	604
Level 3
Assets:
Total	0	0
Other liabilities:
Total	0	0
Level 3 | Foreign exchange forwards | Prepaid expenses and other
Assets:
Derivative asset	0
Level 3 | Foreign exchange forwards | Other assets
Assets:
Derivative asset		0
Level 3 | Fixed income securities | Other assets
Assets:
Debt securities, available-for-sale	0	0
Level 3 | Interest rate swaps | Prepaid expenses and other
Assets:
Derivative asset	0
Level 3 | Interest rate swaps | Other assets
Assets:
Derivative asset	0	0
Level 3 | Interest rate swaps | Other liabilities
Other liabilities:
Derivative liabilities	0	0
Level 3 | Cross currency swaps | Other assets
Assets:
Derivative asset	0	0
Level 3 | Cross currency swaps | Other liabilities
Other liabilities:
Derivative liabilities	0	0
Level 3 | Forward starting interest rate swaps | Other current liabilities
Other liabilities:
Derivative liabilities	0
Level 3 | Forward starting interest rate swaps | Other liabilities
Other liabilities:
Derivative liabilities	$ 0	$ 0