Stockholders' Equity (Narrative) (Detail) - USD ($) shares in Millions		3 Months Ended
	Feb. 10, 2021	Mar. 31, 2021
Equity [Abstract]
Stock repurchase program, authorized amount		$ 1,800,000,000
Net activity related to restricted stock units (in shares)		0.1
Share repurchased during period		$ 10,000,000
Remaining authorized repurchase amount		$ 66,000,000
Board of Directors Chairman
Equity [Abstract]
Shares issued (in shares)	15.0
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Shares issued (in shares)	15.0