Stockholders' Equity (Narrative) (Detail) - USD ($) shares in Millions		9 Months Ended
	Feb. 10, 2021	Sep. 30, 2021	Aug. 31, 2021
Equity [Abstract]
Stock repurchase program, authorized amount (up to)			$ 3,100,000,000
Net activity related to restricted stock units (in shares)		11.7
Share repurchased during period		$ 1,000,000,000
Remaining authorized repurchase amount		$ 397,000,000
Board of Directors Chairman
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]
Shares issued (in shares)	15.0