Changes in Accumulated Other Comprehensive Loss - Changes in AOCI by Component (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020
Changes in accumulated other comprehensive loss by component
Beginning balance	$ 8,760,669	$ 12,163,846
Ending balance	6,467,498	8,328,594
Changes related to cash flow derivative hedges
Changes in accumulated other comprehensive loss by component
Beginning balance	(650,519)	(688,529)
Other comprehensive income (loss) before reclassifications	23,752	(172,323)
Amounts reclassified from accumulated other comprehensive loss	24,762	62,184
Net current-period other comprehensive income (loss)	48,514	(110,139)
Ending balance	(602,005)	(798,668)
Changes in defined benefit plans
Changes in accumulated other comprehensive loss by component
Beginning balance	(65,542)	(45,558)
Other comprehensive income (loss) before reclassifications	313	(18,503)
Amounts reclassified from accumulated other comprehensive loss	3,435	1,550
Net current-period other comprehensive income (loss)	3,748	(16,953)
Ending balance	(61,794)	(62,511)
Foreign currency translation adjustments
Changes in accumulated other comprehensive loss by component
Beginning balance	(23,280)	(63,626)
Other comprehensive income (loss) before reclassifications	11,255	(13,346)
Amounts reclassified from accumulated other comprehensive loss	0	69,044
Net current-period other comprehensive income (loss)	11,255	55,698
Ending balance	(12,025)	(7,928)
Accumulated other comprehensive loss
Changes in accumulated other comprehensive loss by component
Beginning balance	(739,341)	(797,713)
Other comprehensive income (loss) before reclassifications	35,320	(204,172)
Amounts reclassified from accumulated other comprehensive loss	28,197	132,778
Net current-period other comprehensive income (loss)	63,517	(71,394)
Ending balance	$ (675,824)	$ (869,107)