Quarterly Results (unaudited) (Tables)

12 Months Ended

Dec. 31, 2019

Quarterly Financial Information Disclosure [Abstract]

Quarterly Results

	First Quarter				Second Quarter				Third Quarter				Fourth Quarter
($ in millions, except per share data)	2019		2018		2019		2018		2019		2018		2019		2018
Revenues	$	10,990	$	9,770	$	11,144	$	10,099	$	11,069	$	10,465	$	11,472	$	9,481
Net income (loss) applicable to common shareholders	1,261		977		821		678		889		942		1,707		(585		)
Earnings per common share - Basic	3.79		2.76		2.47		1.94		2.71		2.72		5.32		(1.71		)
Earnings per common share - Diluted	3.74		2.71		2.44		1.91		2.67		2.68		5.23		(1.71		)