Stockholders' Equity (Narrative) (Detail) - USD ($) shares in Thousands		3 Months Ended	6 Months Ended
	Feb. 10, 2021	Jun. 30, 2021	Jun. 30, 2021
Equity [Abstract]
Stock repurchase program, authorized amount (up to)		$ 2,100,000,000	$ 2,100,000,000
Net activity related to restricted stock units (in shares)		8,000	100
Share repurchased during period			$ 10,000,000
Remaining authorized repurchase amount		$ 391,000,000	$ 391,000,000
Board of Directors Chairman
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Shares issued (in shares)	15,000