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, 2020		$ 23,743,000	$ 38,771,000	$ 2,502,000	$ (35,815,000)
Shareholders' Equity [Roll Forward]
Employee share-based compensation		169,000
Compensation amortization under share-based plans and other changes		90,000
Net income	$ 1,667,000		1,667,000
Dividends			(440,000)
Other			0
Other comprehensive income (loss)	(733,000)			(733,000)
Treasury stock acquired — share repurchase authorizations					(756,000)
Net shares acquired related to employee share-based compensation plans					(42,000)
Balance, end of period at Jun. 30, 2021	29,156,000	24,002,000	39,998,000	1,769,000	(36,613,000)
Balance, beginning of year (in shares) at Dec. 31, 2020						252.4
Common shares outstanding
Treasury stock acquired - share repurchase authorizations (in shares)						(5.0)
Net shares issued under employee share-based compensation plans (in shares)						2.1
Balance, end of period (in shares) at Jun. 30, 2021						249.5
Balance, beginning of period at Mar. 31, 2021		23,905,000	39,285,000	1,291,000	(36,212,000)
Shareholders' Equity [Roll Forward]
Employee share-based compensation		61,000
Compensation amortization under share-based plans and other changes		36,000
Net income	934,000		934,000
Dividends			(224,000)
Other			3,000
Other comprehensive income (loss)	478,000			478,000
Treasury stock acquired — share repurchase authorizations					(400,000)
Net shares acquired related to employee share-based compensation plans					(1,000)
Balance, end of period at Jun. 30, 2021	29,156,000	24,002,000	39,998,000	1,769,000	(36,613,000)
Balance, beginning of year (in shares) at Mar. 31, 2021						251.5
Common shares outstanding
Treasury stock acquired - share repurchase authorizations (in shares)						(2.6)
Net shares issued under employee share-based compensation plans (in shares)						0.6
Balance, end of period (in shares) at Jun. 30, 2021						249.5
Balance, beginning of period at Dec. 31, 2021	28,887,000	24,154,000	41,555,000	1,193,000	(38,015,000)
Shareholders' Equity [Roll Forward]
Employee share-based compensation		165,000
Compensation amortization under share-based plans and other changes		100,000
Net income	1,569,000		1,569,000
Dividends			(439,000)
Other			(1,000)
Other comprehensive income (loss)	(6,348,000)			(6,348,000)
Treasury stock acquired — share repurchase authorizations	(1,000,000)				(1,000,000)
Net shares acquired related to employee share-based compensation plans	(59,000)				(59,000)
Balance, end of period at Jun. 30, 2022	$ 22,874,000	24,419,000	42,684,000	(5,155,000)	(39,074,000)
Balance, beginning of year (in shares) at Dec. 31, 2021	241.2					241.2
Common shares outstanding
Treasury stock acquired - share repurchase authorizations (in shares)	(5.8)					(5.8)
Net shares issued under employee share-based compensation plans (in shares)						1.9
Balance, end of period (in shares) at Jun. 30, 2022	237.3					237.3
Balance, beginning of period at Mar. 31, 2022		24,348,000	42,359,000	(2,602,000)	(38,574,000)
Shareholders' Equity [Roll Forward]
Employee share-based compensation		30,000
Compensation amortization under share-based plans and other changes		41,000
Net income	$ 551,000		551,000
Dividends			(225,000)
Other			(1,000)
Other comprehensive income (loss)	(2,553,000)			(2,553,000)
Treasury stock acquired — share repurchase authorizations	(500,000)				(500,000)
Net shares acquired related to employee share-based compensation plans	(414)				0
Balance, end of period at Jun. 30, 2022	$ 22,874,000	$ 24,419,000	$ 42,684,000	$ (5,155,000)	$ (39,074,000)
Balance, beginning of year (in shares) at Mar. 31, 2022						240.0
Common shares outstanding
Treasury stock acquired - share repurchase authorizations (in shares)	(2.9)					(2.9)
Net shares issued under employee share-based compensation plans (in shares)						0.2
Balance, end of period (in shares) at Jun. 30, 2022	237.3					237.3