Restructuring And Other Charges (Tables)

12 Months Ended

Dec. 31, 2018

Restructuring And Other Charges [Abstract]

Changes In Restructuring Reserve

	Restructuring
($ in millions)	Liability
Balance, January 1, 2017	$	47
Severance costs		68
Cash payments during the period		(90)
Balance, December 31, 2017		25
Severance costs		12
Transformation costs		23
Cash payments during the period		(42)
Balance, December 31, 2018	$	18