Cash Equivalents and Investments (Detail) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2020	Dec. 31, 2019
Cash and Cash Equivalents [Line Items]
Fair Value	$ 46	$ 3
Cash and cash equivalents	2,099	1,832
Short-term investments	100	98
Certificates of deposit and money market deposit accounts
Cash and Cash Equivalents [Line Items]
Cost	1,128	971
Gains/(Losses)	0	0
Fair Value	1,128	971
Cash and cash equivalents	1,028	866
Short-term investments	97	95
Other assets	3	10
Mutual funds
Cash and Cash Equivalents [Line Items]
Cost	46	3
Gains/(Losses)	0	0
Fair Value	46	3
Cash and cash equivalents	0	0
Short-term investments	3	3
Other assets	$ 43	$ 0