Accounting Policies - Accumulated Other Comprehensive Loss by Component, Net of Tax (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	$ 9,780,446	$ 2,869,075	$ 2,988,229	$ 2,828,532	$ 2,869,075	$ 2,828,532
Other comprehensive income (loss) before reclassifications					(33,698)	(112,827)
Amounts reclassified from accumulated other comprehensive income					1,101	1,618
Net current period other comprehensive income (loss)	19,820	(52,417)	(190,217)	79,008	(32,597)	(111,209)
Ending Balance	9,835,157	9,780,446	2,874,628	2,988,229	9,835,157	2,874,628
Foreign currency translation
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance		(202,204)		5,063	(202,204)	5,063
Other comprehensive income (loss) before reclassifications					(27,721)	(114,811)
Amounts reclassified from accumulated other comprehensive income					0	0
Net current period other comprehensive income (loss)					(27,721)	(114,811)
Ending Balance	(229,925)		(109,748)		(229,925)	(109,748)
Derivative contracts
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance		(53)		4,015	(53)	4,015
Other comprehensive income (loss) before reclassifications					(3,128)	(4,760)
Amounts reclassified from accumulated other comprehensive income					0	579
Net current period other comprehensive income (loss)					(3,128)	(4,181)
Ending Balance	(3,181)		(166)		(3,181)	(166)
Pension and post retirement benefit plans
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance		(54,326)		(54,070)	(54,326)	(54,070)
Other comprehensive income (loss) before reclassifications					(2,849)	6,744
Amounts reclassified from accumulated other comprehensive income					1,101	1,039
Net current period other comprehensive income (loss)					(1,748)	7,783
Ending Balance	(56,074)		(46,287)		(56,074)	(46,287)
AOCI Attributable to Parent
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning Balance	(309,000)	(256,583)	34,016	(44,992)	(256,583)	(44,992)
Net current period other comprehensive income (loss)	19,820	(52,417)	(190,217)	79,008
Ending Balance	$ (289,180)	$ (309,000)	$ (156,201)	$ 34,016	$ (289,180)	$ (156,201)

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Amount after tax, before reclassification adjustments of other comprehensive income (loss).

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Amount after tax and reclassification adjustments of other comprehensive income (loss).

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Amount of stockholders' equity (deficit), net of receivables from officers, directors, owners, and affiliates of the entity, attributable to both the parent and noncontrolling interests. Amount excludes temporary equity. Alternate caption for the concept is permanent equity.

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