Intangible Assets (Narrative) (Details) $ in Millions	3 Months Ended
	Jun. 30, 2018 USD ($)
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Goodwill, Period Increase (Decrease)	$ 0
Other, Net [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Gain (Loss) on Disposition of Intangible Assets	$ 479