Quarterly Financial Data (Unaudited) (Tables)

12 Months Ended

Dec. 31, 2019

Quarterly Financial Information Disclosure [Abstract]

Schedule of quarterly financial information

	First Quarter			Second Quarter	Third Quarter	Fourth Quarter		Total
	(Dollars in millions, except per share amounts)
2019
Operating revenue	$	5,647		5,578	5,606	5,570		22,401
Operating (loss) income	(5,499		)	976	950	847		(2,726	)
Net (loss) income	(6,165		)	371	302	223		(5,269	)
Basic (loss) earnings per common share	(5.77		)	0.35	0.28	0.21		(4.92	)
Diluted (loss) earnings per common share	(5.77		)	0.35	0.28	0.21		(4.92	)
2018
Operating revenue	$	5,945		5,902	5,818	5,778		23,443
Operating income (loss)	750			767	894	(1,841	)	570
Net income (loss)	115			292	272	(2,412	)	(1,733	)
Basic earnings (loss) per common share	0.11			0.27	0.25	(2.26	)	(1.63	)
Diluted earnings (loss) per common share	0.11			0.27	0.25	(2.26	)	(1.63	)