Employee Benefit Plans (Summary of Activity in Corporation's Active Stock Plans) (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock options exercised, number of shares	(267,357)	(399,810)	(987,758)
Director deferred stock units outstanding [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Ending balance, number of shares/units	54,164	45,661	56,301
Beginning balance, number of shares/units	45,661	56,301	52,860
Ending balance, weighted-average grant-date fair value	$ 89.71	$ 87.15	$ 79.21
Beginning balance, weighted-average grant-date fair value	$ 87.15	$ 79.21	$ 75.47
Granted in period, number of shares/units	8,503	5,382	5,940
Granted in period, weighted-average grant-date fair value	$ 103.47	$ 133.67	$ 117.90
Stock awards exercised/vested in period, number of shares	0	(16,022)	(2,499)
Stock awards exercised/vested in period, weighted-average grant date fair value	$ 0	$ 74.89	$ 92.03
Non-Vested Stock Awards/ Stock Units Outstanding [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Ending balance, number of shares/units	566,806	465,319	449,337
Beginning balance, number of shares/units	465,319	449,337	470,359
Ending balance, weighted-average grant-date fair value	$ 99.77	$ 105.36	$ 93.05
Beginning balance, weighted-average grant-date fair value	$ 105.36	$ 93.05	$ 86.24
Granted in period, number of shares/units	217,561	119,176	95,258
Granted in period, weighted-average grant-date fair value	$ 85.39	$ 142.56	$ 130.36
Stock awards exercised/vested in period, number of shares	(108,920)	(97,154)	(88,250)
Stock awards exercised/vested in period, weighted-average grant date fair value	$ 94.00	$ 94.81	$ 98.90
Forfeited/expired in period, number of shares/units	(7,154)	(6,040)	(28,030)
Forfeited/expired in period, weighted-average grant date fair value	$ 114.53	$ 93.28	$ 87.08
Share-based Payment Arrangement, Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Ending balance, number of shares	485,941	616,227	877,681
Beginning balance, number of shares	616,227	877,681	1,739,559
Ending balance, weighted-average exercise price	$ 71.25	$ 71.27	$ 69.02
Beginning balance, weighted-average exercise price	$ 71.27	$ 69.02	$ 66.11
Stock options exercised, number of shares	(130,286)	(261,454)	(861,878)
Stock options exercised, weighted-average exercise price	$ 71.37	$ 63.72	$ 63.14
Maximum [Member] | Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Ending balance, number of shares/units	267,054	213,749	202,460
Beginning balance, number of shares/units	213,749	202,460	201,257
Ending balance, weighted-average grant-date fair value	$ 89.99	$ 96.20	$ 84.71
Beginning balance, weighted-average grant-date fair value	$ 96.20	$ 84.71	$ 77.18
Granted in period, number of shares/units	99,710	52,527	46,086
Granted in period, weighted-average grant-date fair value	$ 74.71	$ 133.40	$ 121.46
Stock awards exercised/vested in period, number of shares	(28,151)	(25,180)	(35,131)
Stock awards exercised/vested in period, weighted-average grant date fair value	$ 85.74	$ 87.18	$ 92.27
Forfeited/expired in period, number of shares/units	(18,254)	(16,058)	(9,752)
Forfeited/expired in period, weighted-average grant date fair value	$ 85.74	$ 87.18	$ 75.70