LT Debt (Tables)

12 Months Ended

Dec. 31, 2018

Debt Disclosure [Abstract]

Schedule of Long-term Debt Instruments [Text Block]

Long-term debt consists of the following at December 31:

	2018		2017
Asset securitization program	$	810,000	$	490,000
6.00% notes, due 2020	209,147		208,971
5.125% notes, due 2021	130,546		130,400
3.50% notes, due 2022	347,288		346,518
4.50% notes, due 2023	297,622		297,122
3.25% notes, due 2024	494,091		493,161
4.00% notes, due 2025	345,762		345,182
7.50% senior debentures, due 2027	109,776		109,694
3.875% notes, due 2028	494,095		493,563
Other obligations with various interest rates and due dates	788		18,434
	$	3,239,115	$	2,933,045

Schedule of Fair Value of Debt [Text Block]

The estimated fair market value of long-term debt at December 31, using quoted market prices, is as follows:

	2018		2017
3.00% notes, due 2018	$	—	$	300,500
6.00% notes, due 2020	214,500		224,000
5.125% notes, due 2021	134,500		139,000
3.50% notes, due 2022	345,000		355,000
4.50% notes, due 2023	303,500		315,500
3.25% notes, due 2024	467,000		491,000
4.00% notes, due 2025	340,500		356,500
7.50% senior debentures, due 2027	128,000		138,500
3.875% notes, due 2028	458,500		501,000