Retrospective Application of Change in Accounting Policy (Tables)

12 Months Ended

Dec. 31, 2016

New Accounting Pronouncements and Changes in Accounting Principles [Abstract]

Schedule of New Accounting Pronouncements and Changes in Accounting Principles [Table Text Block]

The following table provides information regarding the impact of this retrospective application of change in accounting policy on selected consolidated financial data:

		2016				2015				2014
Year Ended December 31, 2016		As previously reported1		As adjusted		As previously reported1		As adjusted		As previously reported1		As adjusted
(Dollars in millions)
Operating Revenues
	Service	$	3,999	$	4,050	$	4,322		4,356		4,329		4,338
	Total operating revenues		5,104		5,155		5,176		5,210		5,009		5,018
Operating income (loss)			60		111		397		431		(190)		(181)
Investment and other income (expenses)
	Interest and dividend income		62		11		39		5		17		8
	Total investment and other income		32		(19)		38		4		38		29
1	In Annual Report on Form 10-K for the year ended December 31, 2016, filed on February 24, 2017.