Consolidated Statement of Changes in Shareholders' Equity (Unaudited) - USD ($) $ in Thousands, shares in Millions	Total	Common stock [Member]	Retained earnings [Member]	Accumulated other comprehensive income (loss), net of tax [Member]	Treasury stock, at cost [Member]	Common shares outstanding [Member]
Balance, beginning of period at Dec. 31, 2021		$ 24,154,000	$ 41,555,000	$ 1,193,000	$ (38,015,000)
Shareholders' Equity [Roll Forward]
Employee share-based compensation		176,000
Compensation amortization under share-based plans and other changes		142,000
Net income	$ 2,023,000		2,023,000
Dividends			(660,000)
Other			(1,000)
Other comprehensive loss	(9,101,000)			(9,101,000)
Treasury stock acquired — share repurchase authorizations					(1,500,000)
Net shares acquired related to employee share-based compensation plans					(60,000)
Balance, end of period at Sep. 30, 2022	19,906,000	24,472,000	42,917,000	(7,908,000)	(39,575,000)
Balance, beginning of period (in shares) at Dec. 31, 2021						241.2
Common shares outstanding
Treasury stock acquired - share repurchase authorizations (in shares)						(8.9)
Net shares issued under employee share-based compensation plans (in shares)						2.0
Balance, end of period (in shares) at Sep. 30, 2022						234.3
Balance, beginning of period at Jun. 30, 2022		24,419,000	42,684,000	(5,155,000)	(39,074,000)
Shareholders' Equity [Roll Forward]
Employee share-based compensation		11,000
Compensation amortization under share-based plans and other changes		42,000
Net income	454,000		454,000
Dividends			(221,000)
Other			0
Other comprehensive loss	(2,753,000)			(2,753,000)
Treasury stock acquired — share repurchase authorizations					(500,000)
Net shares acquired related to employee share-based compensation plans					(1,000)
Balance, end of period at Sep. 30, 2022	19,906,000	24,472,000	42,917,000	(7,908,000)	(39,575,000)
Balance, beginning of period (in shares) at Jun. 30, 2022						237.3
Common shares outstanding
Treasury stock acquired - share repurchase authorizations (in shares)						(3.1)
Net shares issued under employee share-based compensation plans (in shares)						0.1
Balance, end of period (in shares) at Sep. 30, 2022						234.3
Balance, beginning of period at Dec. 31, 2022	21,560,000	24,565,000	43,516,000	(6,445,000)	(40,076,000)
Shareholders' Equity [Roll Forward]
Employee share-based compensation		102,000
Compensation amortization under share-based plans and other changes		164,000
Net income	1,365,000		1,365,000
Dividends			(683,000)
Other			0
Other comprehensive loss	(1,567,000)			(1,567,000)
Treasury stock acquired — share repurchase authorizations	(900,000)				(900,000)
Net shares acquired related to employee share-based compensation plans	(63,000)				(63,000)
Balance, end of period at Sep. 30, 2023	$ 19,978,000	24,831,000	44,198,000	(8,012,000)	(41,039,000)
Balance, beginning of period (in shares) at Dec. 31, 2022	232.1					232.1
Common shares outstanding
Treasury stock acquired - share repurchase authorizations (in shares)	(5.0)					(5.0)
Net shares issued under employee share-based compensation plans (in shares)						1.3
Balance, end of period (in shares) at Sep. 30, 2023	228.4					228.4
Balance, beginning of period at Jun. 30, 2023		24,776,000	44,026,000	(6,009,000)	(40,938,000)
Shareholders' Equity [Roll Forward]
Employee share-based compensation		8,000
Compensation amortization under share-based plans and other changes		47,000
Net income	$ 404,000		404,000
Dividends			(232,000)
Other			0
Other comprehensive loss	(2,003,000)			(2,003,000)
Treasury stock acquired — share repurchase authorizations	(100,000)				(100,000)
Net shares acquired related to employee share-based compensation plans	(926)				(1,000)
Balance, end of period at Sep. 30, 2023	$ 19,978,000	$ 24,831,000	$ 44,198,000	$ (8,012,000)	$ (41,039,000)
Balance, beginning of period (in shares) at Jun. 30, 2023						228.9
Common shares outstanding
Treasury stock acquired - share repurchase authorizations (in shares)	(0.6)					(0.6)
Net shares issued under employee share-based compensation plans (in shares)						0.1
Balance, end of period (in shares) at Sep. 30, 2023	228.4					228.4