Consolidated Statements of Operations - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Income Statement [Abstract]
Revenues	$ 3,343	$ 3,588
Cost and expenses:
Operating	2,074	2,272
Selling, general and administrative	510	503
Depreciation and amortization	55	57
Other operating items, net	0	(9)
Total costs and expenses	2,639	2,823
Operating income (loss)	704	765
Interest expense	(109)	(100)
Interest income	13	7
Other items, net	1	(3)
Earnings from continuing operations before income taxes and equity in loss of investee companies	609	669
Provision for income taxes	(138)	(206)
Equity in loss of investee companies, net of tax	(17)	(21)
Net earnings from continuing operations	454	442
Net earnings (loss) from discontinued operations, net of tax (Note 3)	(706)	31
Net earnings (loss)	$ (252)	$ 473
Basic net earnings (loss) per common share:
Basic net earnings per common share from continuing operations (in dollars per share)	$ 1.11	$ 0.96
Basic net earnings (loss) per common share from discontinued operations (in dollars per share)	(1.72)	0.07
Basic net earnings (loss) per common share (in dollars per share)	(0.61)	1.03
Diluted net earnings (loss) per common share:
Diluted net earnings per common share from continuing operations (in dollars per share)	1.09	0.95
Diluted net earnings (loss) per common share from discontinued operations (in dollars per share)	(1.70)	0.07
Diluted net earnings (loss) per common share (in dollars per share)	$ (0.61)	$ 1.02
Weighted average number of common shares outstanding:
Basic weighted average number of common shares outstanding	410	459
Diluted weighted average number of common shares outstanding	416	464
Dividends per common share (in dollars per share)	$ 0.18	$ 0.15