Statements of Condensed Consolidated Equity (Unaudited) - USD ($) shares in Thousands, $ in Thousands		Total	Cumulative Effect, Period of Adoption Balance	[1]	Common Stock	Treasury Stock	Retained Earnings	Retained Earnings Cumulative Effect, Period of Adoption Balance	[1]	Accumulated Other Comprehensive (Loss) Income	Accumulated Other Comprehensive (Loss) Income Cumulative Effect, Period of Adoption Balance	[1]
Beginning balance at Dec. 31, 2018		$ 10,958,229			$ 7,828,554	$ (49,194)	$ 3,184,275			$ (5,406)
Beginning Balance (in shares) at Dec. 31, 2018					254,472
Comprehensive income, net of tax:
Net (loss) income		190,691					190,691
Comprehensive income, net of tax:
Net change in interest rate cash flow hedges, net of tax expense		42								42
Other post-retirement benefit liability adjustment, net of tax expense		76								76
Dividends	[1]	(7,652)					(7,652)
Share-based compensation plans		(1,798)			$ (11,327)	9,529
Stock-based compensation plans (in shares)					527
Ending balance at Mar. 31, 2019		11,139,588			$ 7,817,227	(39,665)	3,367,810			(5,784)
Ending Balance (in shares) at Mar. 31, 2019					254,999
Beginning balance at Dec. 31, 2019		9,803,588	$ 0		$ 7,818,205	(32,507)	2,023,089	$ 496		(5,199)	$ (496)
Beginning Balance (in shares) at Dec. 31, 2019					255,171
Comprehensive income, net of tax:
Net (loss) income		(167,139)					(167,139)
Comprehensive income, net of tax:
Net change in interest rate cash flow hedges, net of tax expense		0
Other post-retirement benefit liability adjustment, net of tax expense		12								12
Dividends	[1]	(7,664)					(7,664)
Share-based compensation plans		5,081			$ 3,426	1,655
Stock-based compensation plans (in shares)					91
Ending balance at Mar. 31, 2020		$ 9,633,878			$ 7,821,631	$ (30,852)	$ 1,848,286			$ (5,187)
Ending Balance (in shares) at Mar. 31, 2020					255,262

[1] (a)Related to adoption of ASU 2018-02.