CONSOLIDATED BALANCE SHEET - 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
Current assets
Cash and cash equivalents ($392,772 and $391,635 related to VIEs)	$ 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 ($66 and $202,481 related to VIEs)	7,262	47,873	73,098	98,733	214,828	243,048	101,124	142,503
Accounts and notes receivable, net ($300,082 and $199,108 related to VIEs)	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 ($247,800 and $281,713 related to VIEs)	882,030	940,635	830,718	1,082,197	1,007,469	915,811	899,370	914,127
Other current assets ($21,700 and $6,624 related to VIEs)	359,371	345,653	364,904	291,303	308,905	403,751	458,427	499,137
Current assets held for sale ($105,243 and $79,269 related to VIEs)	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
Noncurrent assets
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 assets ($45,178 and $26,447 related to VIEs)	478,616	494,144	604,897	603,740	312,907	331,591	366,373	367,515
Noncurrent assets held for sale ($12,931 related to VIEs in 2018)	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
Current liabilities
Accounts payable ($446,185 and $419,590 related to VIEs)	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 ($231,521 and $249,831 related to VIEs)	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 ($28,538 and $25,341 related to VIEs)	541,024	589,167	550,427	599,656	587,491	615,026	563,940	662,692
Other accrued liabilities ($20,855 and $49,968 related to VIEs)	452,586	414,196	404,775	396,751	361,995	386,507	380,550	384,108
Current liabilities related to assets held for sale ($72,851 and $79,872 related to VIEs)	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 related to assets held for sale	0	0	28,011	27,382	17,498	18,512	16,714	15,531
Contingencies and commitments
Shareholders' equity
Preferred stock — authorized 20,000,000 shares ($0.01 par value), none issued	0	0	0	0	0	0	0	0
Common stock — authorized 375,000,000 shares ($0.01 par value); issued and outstanding — 140,174,400 and 139,653,824 shares in 2019 and 2018, respectively	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