Other comprehensive income (loss) - Reclassification out of accumulated other comprehensive income - Parenthetical (Details) - USD ($) $ in Thousands		12 Months Ended
	Oct. 15, 2022	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Available-for-sale securities transfer to Held-to-maturity		$ 6,531,092	$ 0	$ 0
US Treasury Securities
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Available-for-sale securities transfer to Held-to-maturity	$ 6,500,000
Available-for-sale securities transfer to Held-to-Maturity at par value	$ 7,400,000