Earnings Per Share (Tables)

12 Months Ended

Dec. 31, 2020

Earnings Per Share [Abstract]

Schedule of Earnings Per Share Basic and Diluted

The following table provides the calculation of earnings per share and the reconciliation of earnings per share and earnings per diluted share for the years ended December 31:

	2020				2019			2018
($ in millions, except per share data)	Income		Average Shares	Per Share Amount	Income	Average Shares	Per Share Amount	Income	Average Shares	Per Share Amount
Earnings Per Share:
Net income available to common shareholders	$	1,323			2,419			2,118
Less: Income allocated to participating securities	6				21			23
Net income allocated to common shareholders	$	1,317	715	1.84	2,398	710	3.38	2,095	673	3.11
Earnings Per Diluted Share:
Net income available to common shareholders	$	1,323			2,419			2,118
Effect of dilutive securities:
Stock-based awards	—		5		—	10		—	12
Net income available to common shareholders plus assumed conversions	1,323				2,419			2,118
Less: Income allocated to participating securities	6				21			23
Net income allocated to common shareholders plus assumed conversions	$	1,317	720	1.83	2,398	720	3.33	2,095	685	3.06