Statements of Condensed Consolidated Equity (Unaudited) - USD ($) shares in Thousands, $ in Thousands		Total		Cumulative Effect, Period of Adoption, Adjustment	Common Stock	Treasury Stock	Retained Earnings	Retained Earnings Cumulative Effect, Period of Adoption, Adjustment	Accumulated Other Comprehensive Loss	Accumulated Other Comprehensive Loss Cumulative Effect, Period of Adoption, Adjustment
Comprehensive income, net of tax:
Change in accounting principle	[1]			$ 0				$ 496		$ (496)
Beginning balance (in shares) at Dec. 31, 2018					254,472
Beginning balance at Dec. 31, 2018		$ 10,958,229			$ 7,828,554	$ (49,194)	$ 3,184,275		$ (5,406)
Comprehensive income, net of tax:
Net (loss) income		316,257					316,257
Comprehensive income, net of tax:
Net change in interest rate cash flow hedges, net of tax expense		84	[2]						84
Other post-retirement benefit liability adjustment, net of tax expense		152	[3]						152
Dividends		(15,317)					(15,317)
Share-based compensation plans		3,540			$ (6,344)	9,884
Share-based compensation plans (in shares)					546
Other (in shares)					(222)
Other					$ (14,470)
Ending balance (in shares) at Jun. 30, 2019					254,796
Ending balance at Jun. 30, 2019		11,248,475			$ 7,807,740	(39,310)	3,485,711		(5,666)
Beginning balance (in shares) at Mar. 31, 2019					254,999
Beginning balance at Mar. 31, 2019		11,139,588			$ 7,817,227	(39,665)	3,367,810		(5,784)
Comprehensive income, net of tax:
Net (loss) income		125,566					125,566
Comprehensive income, net of tax:
Net change in interest rate cash flow hedges, net of tax expense		42	[2]						42
Other post-retirement benefit liability adjustment, net of tax expense		76	[3]						76
Dividends		(7,665)					(7,665)
Share-based compensation plans		5,338			$ 4,983	355
Share-based compensation plans (in shares)					19
Other (in shares)					(222)
Other		(14,470)			$ (14,470)
Ending balance (in shares) at Jun. 30, 2019					254,796
Ending balance at Jun. 30, 2019		11,248,475			$ 7,807,740	(39,310)	3,485,711		(5,666)
Beginning balance (in shares) at Dec. 31, 2019					255,171
Beginning balance at Dec. 31, 2019		9,803,588			$ 7,818,205	(32,507)	2,023,089		(5,199)
Comprehensive income, net of tax:
Net (loss) income		(430,214)					(430,214)
Comprehensive income, net of tax:
Net change in interest rate cash flow hedges, net of tax expense	[2]	0
Other post-retirement benefit liability adjustment, net of tax expense		84	[3]						84
Dividends		(7,664)					(7,664)
Share-based compensation plans		9,388			$ 7,222	2,166
Share-based compensation plans (in shares)					119
Equity component of convertible senior notes (See Note 6)		63,645			$ 63,645
Ending balance (in shares) at Jun. 30, 2020					255,290
Ending balance at Jun. 30, 2020		9,438,827			$ 7,889,072	(30,341)	1,585,211		(5,115)
Beginning balance (in shares) at Mar. 31, 2020					255,262
Beginning balance at Mar. 31, 2020		9,633,878			$ 7,821,631	(30,852)	1,848,286		(5,187)
Comprehensive income, net of tax:
Net (loss) income		(263,075)					(263,075)
Comprehensive income, net of tax:
Net change in interest rate cash flow hedges, net of tax expense	[2]	0
Other post-retirement benefit liability adjustment, net of tax expense		72	[3]						72
Share-based compensation plans		4,307			$ 3,796	511
Share-based compensation plans (in shares)					28
Equity component of convertible senior notes (See Note 6)		63,645			$ 63,645
Ending balance (in shares) at Jun. 30, 2020					255,290
Ending balance at Jun. 30, 2020		$ 9,438,827			$ 7,889,072	$ (30,341)	$ 1,585,211		$ (5,115)

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

[2] Net of tax expense of $10 and $20 for the three and six months ended June 30, 2019.

[3] Net of tax expense of $24 and $26 for the three months ended June 30, 2020 and 2019, respectively, and $48 and $52 for the six months ended June 30, 2020 and 2019, respectively.