Fair Value Of Financial Instruments (Tables)

6 Months Ended

Jun. 30, 2019

Fair Value Of Financial Instruments [Abstract]

Fair Value Of Long-Term Debt

	June 30, 2019				December 31, 2018
($ in millions)		Carrying Amount		Fair Value		Carrying Amount		Fair Value
Total debt	$	17,026	$	12,822	$	17,400	$	12,756