Comprehensive Income - Accumulated Other Comprehensive Income (Loss), Net (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	$ 17,903,405	$ 16,187,283	$ 15,716,649
Net gain (loss) during period	(662,452)	(64,546)	143,648
Ending balance	25,317,990	17,903,405	16,187,283
Investment Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	77,625	144,602	(37,380)
Net gain (loss) during period	(406,793)	(66,977)	107,222
Ending balance	(329,168)	77,625	144,602
Defined Benefit Plans [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(267,145)	(481,064)	(342,419)
Net gain (loss) during period	64,959	213,919	(138,645)
Ending balance	(202,186)	(267,145)	(481,064)
Accumulated Other Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	61,942	273,430	(98,359)
Net gain (loss) during period	(320,618)	(211,488)	175,071
Ending balance	258,676	61,942	273,430
Accumulated Other Comprehensive Income (Loss), Net [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(127,578)	(63,032)	(206,680)
Net gain (loss) during period	(662,452)	(64,546)	143,648
Ending balance	$ (790,030)	$ (127,578)	$ (63,032)