Discontinued Operations Income Statement (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Expenses
Net income from discontinued operations	$ 6	$ 40
Tempo Business | Discontinued Operations, Disposed of by Sale
Revenue
Total revenue	0	527
Expenses
Total operating expenses	3	470
Income (loss) from discontinued operations before income taxes	(3)	57
Income tax expense (benefit)	(1)	17
Income (loss) from discontinued operations excluding gain, net of tax	(2)	40
Gain on sale of discontinued operations, net of tax	8	0
Net income from discontinued operations	$ 6	$ 40