Stock-based compensation plans (Tables)

12 Months Ended

Dec. 31, 2024

Share-Based Payment Arrangement [Abstract]

Summary of Restricted Stock and Restricted Stock Unit Activity

A summary of restricted stock and restricted stock unit activity follows:

	Restricted Stock Units Outstanding	Weighted- Average Grant Price		Restricted Stock Outstanding	Weighted- Average Grant Price
Unvested at January 1, 2024	1,330,278	$	154.46	31,715	$	164.63
Granted	969,427	139.56		—	—
Vested	(696,738)	147.81		(20,836)	164.66
Cancelled	(58,929)	148.75		(267)	161.18
Unvested at December 31, 2024	1,544,038	148.33		10,612	164.66

Summary of Stock Option Activity

Select information on employee stock-based compensation plans is summarized in the following table.

(Dollars in millions)	2024		2023		2022
Stock-based compensation expense (a)	$	116	$	118	$	111
Income tax benefits recognized	25		24		26
Cash received from exercised stock options	138		32		37
Fair value of stock-based awards granted	141		124		99
Intrinsic value of vested restricted stock and    restricted stock units and exercised stock options	134		96		125

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(a)    Unrecognized stock-based compensation expense of $48 million at December 31, 2024 is expected to be recognized over a weighted-average period of approximately one year.

A summary of stock option activity follows:

		Weighted-Average
	Stock Options Outstanding	Exercise Price		Life (In Years)	Aggregate Intrinsic Value (In millions)
Outstanding at January 1, 2024	2,198,664	$	152.33
Granted	133,834	138.10
Exercised	(1,026,259)	142.00
Cancelled/Expired	(345,406)	166.48
Outstanding at December 31, 2024	960,833	156.30		6.2	$	30,664
Exercisable at December 31, 2024	654,215	$	158.70	5.3	$	19,371