Income Taxes (Income Tax Benefit (Provision) (Details) - USD ($) $ in Thousands		3 Months Ended			9 Months Ended
		Aug. 31, 2019	Aug. 31, 2018	Feb. 28, 2018	Aug. 31, 2019	Aug. 31, 2018
Income Tax Disclosure [Abstract]
Benefit (provision) for income taxes	[1]	$ 154,440	$ 98,298		$ 374,670	$ 306,870
Effective tax rate		23.10%	17.80%		24.20%	25.40%
Write down of deferred tax asset resulting from Tax Cuts and Jobs Act				$ 68,600		$ 68,600
Income tax benefit from tax accounting method changes and energy credits			$ 34,100
Effective income tax rate excluding impact of Tax Cuts and Jobs Act, accounting method changes, and energy credits						22.60%

[1] Provision for income taxes for the nine months ended August 31, 2018 includes a non-cash one-time write down of deferred tax assets of $68.6 million resulting from the Tax Cuts and Jobs Act enacted in December 2017.