Quarterly Financial Data (Unaudited) - Schedule of Restatements - Balance Sheet Related Items (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Quarterly Data [Line Items]
Cash and cash equivalents	$ 1,997,199	$ 1,805,104	$ 1,857,285	$ 1,805,777	$ 1,764,746	$ 1,679,796	$ 1,681,960	$ 1,685,954
Marketable securities, current	7,262	47,873	73,098	98,733	214,828	243,048	101,124	142,503
Accounts and notes receivable	1,075,254	1,047,146	1,246,562	1,178,106	1,237,248	1,405,053	1,234,584	1,258,136
Contract assets	882,030	940,635	830,718	1,082,197	1,007,469	915,811	899,370	914,127
Other current assets	359,371	345,653	364,904	291,303	308,905	403,751	458,427	499,137
Current assets held for sale	1,195,156	1,147,955	796,777	732,134	837,407	915,100	1,083,043	1,207,948
Total current assets	5,516,272	5,334,366	5,169,344	5,188,250	5,370,603	5,562,559	5,458,508	5,707,805
Property, plant and equipment ($29,393 and $28,679 related to VIEs)	543,040	571,214	677,011	717,738	745,942	748,494	753,885	776,467
Goodwill	450,386	442,809	467,267	467,917	466,452	486,515	491,529	514,519
Investments	574,421	626,043	850,317	903,108	903,136	818,402	863,752	874,360
Deferred taxes	62,688	61,103	503,459	395,474	378,102	464,818	464,832	464,364
Deferred compensation trusts	341,235	359,304	356,727	354,961	328,814	361,740	349,651	345,799
Other noncurrent assets	478,616	494,144	604,897	603,740	312,907	331,591	366,373	367,515
Noncurrent assets held for sale	0	0	350,030	391,002	376,599	385,807	405,567	417,675
Total noncurrent assets	2,450,386	2,554,617	3,809,708	3,833,940	3,511,952	3,597,367	3,695,589	3,760,699
Total assets	7,966,658	7,888,983	8,979,052	9,022,190	8,882,555	9,159,926	9,154,097	9,468,504
Trade accounts payable	1,357,749	1,298,054	1,317,013	1,317,785	1,400,666	1,365,169	1,388,113	1,189,964
Short-term borrowings	38,727	45,240	40,810	35,155	26,887	56,945	80,561	28,808
Contract liabilities	1,120,237	1,096,943	1,363,463	934,848	903,374	973,677	1,060,999	1,276,079
Accrued salaries, wages and benefits	541,024	589,167	550,427	599,656	587,491	615,026	563,940	662,692
Other accrued liabilities	452,586	414,196	404,775	396,751	361,995	386,507	380,550	384,108
Other accrued liabilities	421,738	412,243	385,136	363,382	378,815	403,986	441,085	665,567
Total current liabilities	3,932,061	3,855,843	4,061,624	3,647,577	3,659,228	3,801,310	3,915,248	4,207,218
Long-term debt	1,651,739	1,636,905	1,657,246	1,650,927	1,661,565	1,667,359	1,575,370	1,607,653
Deferred taxes	83,295	0	0	0	0	0	0	0
Other noncurrent liabilities	715,471	712,500	733,433	719,588	564,011	600,074	590,645	594,429
Noncurrent liabilities held for sale	0	0	28,011	27,382	17,498	18,512	16,714	15,531
Preferred stock	0	0	0	0	0	0	0	0
Common stock	1,399	1,399	1,399	1,399	1,396	1,407	1,406	1,406
Additional paid-in capital	165,314	111,857	113,043	94,456	82,106	122,267	111,368	99,028
Accumulated OCI	(379,873)	(553,291)	(511,066)	(498,621)	(543,531)	(483,435)	(423,472)	(373,261)
Retained earnings	1,700,912	1,999,334	2,772,110	3,215,870	3,294,154	3,275,528	3,230,430	3,183,504
Total shareholders' equity	1,487,752	1,559,299	2,375,486	2,813,104	2,834,125	2,915,767	2,919,732	2,910,677
NCI	96,340	124,436	123,252	163,612	146,128	156,904	136,388	132,996
Total equity	1,584,092	1,683,735	2,498,738	2,976,716	2,980,253	3,072,671	3,056,120	3,043,673	$ 3,403,361	$ 3,191,800
Total liabilities and equity	$ 7,966,658	7,888,983	8,979,052	9,022,190	8,882,555	9,159,926	9,154,097	9,468,504
As Previously Reported
Quarterly Data [Line Items]
Cash and cash equivalents		1,805,104	1,857,285	1,805,777	1,764,746	1,679,796	1,681,960	1,685,954
Marketable securities, current		47,873	73,098	98,733	214,828	243,048	101,124	142,503
Accounts and notes receivable		1,045,749	1,245,165	1,176,709	1,235,851	1,403,503	1,233,034	1,256,586
Contract assets		930,554	820,323	1,137,953	1,079,157	938,963	898,248	902,634
Other current assets		345,653	364,904	291,303	308,905	403,751	458,427	499,137
Current assets held for sale		1,147,955	796,777	732,134	837,407	915,100	1,083,043	1,207,948
Total current assets		5,322,888	5,157,552	5,242,609	5,440,894	5,584,161	5,455,836	5,694,762
Property, plant and equipment ($29,393 and $28,679 related to VIEs)		571,214	677,011	717,738	745,942	748,494	753,885	776,467
Goodwill		439,576	464,034	464,684	463,219	482,928	487,942	510,932
Investments		626,043	850,317	903,108	903,136	827,943	873,293	876,401
Deferred taxes		70,538	513,306	363,873	342,126	425,312	426,669	435,675
Deferred compensation trusts		359,304	356,727	354,961	328,814	361,740	349,651	345,799
Other noncurrent assets		494,144	604,897	603,740	312,907	331,591	366,373	367,515
Noncurrent assets held for sale		0	350,030	391,002	376,599	385,807	405,567	417,675
Total noncurrent assets		2,560,819	3,816,322	3,799,106	3,472,743	3,563,815	3,663,380	3,730,464
Total assets		7,883,707	8,973,874	9,041,715	8,913,637	9,147,976	9,119,216	9,425,226
Trade accounts payable		1,298,054	1,317,013	1,317,785	1,400,666	1,365,169	1,388,113	1,189,964
Short-term borrowings		45,240	40,810	35,155	26,887	56,945	80,561	28,808
Contract liabilities		1,095,889	1,363,414	819,043	800,539	839,928	902,856	1,152,626
Accrued salaries, wages and benefits		579,592	540,852	590,081	577,916	604,535	553,449	652,201
Other accrued liabilities		419,351	410,469	402,445	367,689	391,540	385,583	389,141
Other accrued liabilities		412,243	385,136	363,382	378,815	403,986	441,085	665,567
Total current liabilities		3,850,369	4,057,694	3,527,891	3,552,512	3,662,103	3,751,647	4,078,307
Long-term debt		1,636,905	1,657,246	1,650,927	1,661,565	1,667,359	1,575,370	1,607,653
Deferred taxes		0	0	0	0	0	0	0
Other noncurrent liabilities		712,500	733,433	719,588	564,011	600,074	590,645	594,429
Noncurrent liabilities held for sale		0	28,011	27,382	17,498	18,512	16,714	15,531
Preferred stock		0	0	0	0	0	0	0
Common stock		1,399	1,399	1,399	1,396	1,407	1,406	1,406
Additional paid-in capital		111,857	113,043	94,456	82,106	122,267	111,368	99,028
Accumulated OCI		(551,903)	(510,009)	(497,892)	(542,477)	(482,178)	(422,595)	(372,961)
Retained earnings		1,998,144	2,769,805	3,354,352	3,422,157	3,401,528	3,353,175	3,268,837
Total shareholders' equity		1,559,497	2,374,238	2,952,315	2,963,182	3,043,024	3,043,354	2,996,310
NCI		124,436	123,252	163,612	154,869	156,904	141,486	132,996
Total equity		1,683,933	2,497,490	3,115,927	3,118,051	3,199,928	3,184,840	3,129,306		$ 3,242,831
Total liabilities and equity		7,883,707	8,973,874	9,041,715	8,913,637	9,147,976	9,119,216	9,425,226
Radford Adjustments | Restatement Adjustment
Quarterly Data [Line Items]
Cash and cash equivalents		0	0	0	0	0	0	0
Marketable securities, current		0	0	0	0	0	0	0
Accounts and notes receivable		0	0	0	0	0	0	0
Contract assets		(1)	(1)	(66,396)	(67,988)	(33,832)	(9,683)	0
Other current assets		0	0	0	0	0	0	0
Current assets held for sale		0	0	0	0	0	0	0
Total current assets		(1)	(1)	(66,396)	(67,988)	(33,832)	(9,683)	0
Property, plant and equipment ($29,393 and $28,679 related to VIEs)		0	0	0	0	0	0	0
Goodwill		0	0	0	0	0	0	0
Investments		0	0	0	0	0	0	0
Deferred taxes		2,532	2,321	42,596	41,600	36,269	33,635	31,404
Deferred compensation trusts		0	0	0	0	0	0	0
Other noncurrent assets		0	0	0	0	0	0	0
Noncurrent assets held for sale		0	0	0	0	0	0	0
Total noncurrent assets		2,532	2,321	42,596	41,600	36,269	33,635	31,404
Total assets		2,531	2,320	(23,800)	(26,388)	2,437	23,952	31,404
Trade accounts payable		0	0	0	0	0	0	0
Short-term borrowings		0	0	0	0	0	0	0
Contract liabilities		3,916	3,000	111,713	105,787	116,768	129,463	129,446
Accrued salaries, wages and benefits		0	0	0	0	0	0	0
Other accrued liabilities		0	0	0	0	0	0	0
Other accrued liabilities		0	0	0	0	0	0	0
Total current liabilities		3,916	3,000	111,713	105,787	116,768	129,463	129,446
Long-term debt		0	0	0	0	0	0	0
Deferred taxes		0	0	0	0	0	0	0
Other noncurrent liabilities		0	0	0	0	0	0	0
Noncurrent liabilities held for sale		0	0	0	0	0	0	0
Preferred stock		0	0	0	0	0	0	0
Common stock		0	0	0	0	0	0	0
Additional paid-in capital		0	0	0	0	0	0	0
Accumulated OCI		0	0	0	0	0	0	0
Retained earnings		(1,385)	(680)	(135,513)	(132,175)	(114,331)	(105,511)	(98,042)
Total shareholders' equity		(1,385)	(680)	(135,513)	(132,175)	(114,331)	(105,511)	(98,042)
NCI		0	0		0	0	0	0
Total equity		(1,385)	(680)	(135,513)	(132,175)	(114,331)	(105,511)	(98,042)
Total liabilities and equity		2,531	2,320	(23,800)	(26,388)	2,437	23,952	31,404
Infrastructure Adjustments | Restatement Adjustment
Quarterly Data [Line Items]
Cash and cash equivalents					0		0
Marketable securities, current					0		0
Accounts and notes receivable					0		0
Contract assets					(14,099)		0
Other current assets					0		0
Current assets held for sale					0		0
Total current assets					(14,099)		0
Property, plant and equipment ($29,393 and $28,679 related to VIEs)					0		0
Goodwill					0		0
Investments					0		0
Deferred taxes					1,291		1,249
Deferred compensation trusts					0		0
Other noncurrent assets					0		0
Noncurrent assets held for sale					0		0
Total noncurrent assets					1,291		1,249
Total assets					(12,808)		1,249
Trade accounts payable					0		0
Short-term borrowings					0		0
Contract liabilities					0		11,328
Accrued salaries, wages and benefits					0		0
Other accrued liabilities					0		0
Other accrued liabilities					0		0
Total current liabilities					0		11,328
Long-term debt					0		0
Deferred taxes					0		0
Other noncurrent liabilities					0		0
Noncurrent liabilities held for sale					0		0
Preferred stock					0		0
Common stock					0		0
Additional paid-in capital					0		0
Accumulated OCI					0		0
Retained earnings					(4,067)		(4,981)
Total shareholders' equity					(4,067)		(4,981)
NCI					(8,741)		(5,098)
Total equity					(12,808)		(10,079)
Total liabilities and equity					(12,808)		1,249
Energy & Chemicals Adjustments | Restatement Adjustment
Quarterly Data [Line Items]
Cash and cash equivalents				0		0	0
Marketable securities, current				0		0	0
Accounts and notes receivable				0		0	0
Contract assets				0		0	0
Other current assets				0		0	0
Current assets held for sale				0		0	0
Total current assets				0		0	0
Property, plant and equipment ($29,393 and $28,679 related to VIEs)				0		0	0
Goodwill				0		0	0
Investments				0		0	0
Deferred taxes				1,230		3,462	3,533
Deferred compensation trusts				0		0	0
Other noncurrent assets				0		0	0
Noncurrent assets held for sale				0		0	0
Total noncurrent assets				1,230		3,462	3,533
Total assets				1,230		3,462	3,533
Trade accounts payable				0		0	0
Short-term borrowings				0		0	0
Contract liabilities				7,112		20,013	20,419
Accrued salaries, wages and benefits				0		0	0
Other accrued liabilities				0		0	0
Other accrued liabilities				0		0	0
Total current liabilities				7,112		20,013	20,419
Long-term debt				0		0	0
Deferred taxes				0		0	0
Other noncurrent liabilities				0		0	0
Noncurrent liabilities held for sale				0		0	0
Preferred stock				0		0	0
Common stock				0		0	0
Additional paid-in capital				0		0	0
Accumulated OCI				72		(76)	173
Retained earnings				(5,954)		(16,475)	(17,059)
Total shareholders' equity				(5,882)		(16,551)	(16,886)
NCI						0	0
Total equity				(5,882)		(16,551)	(16,886)
Total liabilities and equity				1,230		3,462	3,533
Other Adjustments | Restatement Adjustment
Quarterly Data [Line Items]
Cash and cash equivalents		0	0	0	0	0	0	0
Marketable securities, current		0	0	0	0	0	0	0
Accounts and notes receivable		1,397	1,397	1,397	1,397	1,550	1,550	1,550
Contract assets		10,082	10,396	10,640	10,399	10,680	10,805	11,493
Other current assets		0	0	0	0	0	0	0
Current assets held for sale		0	0	0	0	0	0	0
Total current assets		11,479	11,793	12,037	11,796	12,230	12,355	13,043
Property, plant and equipment ($29,393 and $28,679 related to VIEs)		0	0	0	0	0	0	0
Goodwill		3,233	3,233	3,233	3,233	3,587	3,587	3,587
Investments		0	0	0	0	(9,541)	(9,541)	(2,041)
Deferred taxes		(11,967)	(12,168)	(12,225)	(6,915)	(225)	(254)	(2,715)
Deferred compensation trusts		0	0	0	0	0	0	0
Other noncurrent assets		0	0	0	0	0	0	0
Noncurrent assets held for sale		0	0	0	0	0	0	0
Total noncurrent assets		(8,734)	(8,935)	(8,992)	(3,682)	(6,179)	(6,208)	(1,169)
Total assets		2,745	2,858	3,045	8,114	6,051	6,147	11,874
Trade accounts payable		0	0	0	0	0	0	0
Short-term borrowings		0	0	0	0	0	0	0
Contract liabilities		(2,862)	(2,951)	(3,020)	(2,952)	(3,032)	(3,067)	(5,993)
Accrued salaries, wages and benefits		9,575	9,575	9,575	9,575	10,491	10,491	10,491
Other accrued liabilities		(5,155)	(5,694)	(5,694)	(5,694)	(5,033)	(5,033)	(5,033)
Other accrued liabilities		0	0	0	0	0	0	0
Total current liabilities		1,558	930	861	929	2,426	2,391	(535)
Long-term debt		0	0	0	0	0	0	0
Deferred taxes		0	0	0	0	0	0	0
Other noncurrent liabilities		0	0	0	0	0	0	0
Noncurrent liabilities held for sale		0	0	0	0	0	0	0
Preferred stock		0		0	0	0	0	0
Common stock		0		0	0	0	0	0
Additional paid-in capital		0		0	0	0	0	0
Accumulated OCI		(1,388)	(1,057)	(801)	(1,054)	(1,181)	(1,050)	(300)
Retained earnings		2,575	2,985	2,985	8,239	4,806	4,806	12,709
Total shareholders' equity		1,187	1,928	2,184	7,185	3,625	3,756	12,409
NCI		0	0		0	0	0	0
Total equity		1,187	1,928	2,184	7,185	3,625	3,756	12,409
Total liabilities and equity		$ 2,745	$ 2,858	$ 3,045	$ 8,114	$ 6,051	$ 6,147	$ 11,874