Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2015

Accounting Policies [Abstract]

Computation of basic and diluted earnings per common share

The computation of basic and diluted earnings per common share for the years ended December 31 is presented in the following table.

($ in millions, except per share data)	2015		2014		2013
Numerator:
Net income	$	2,171	$	2,850	$	2,280
Less: Preferred stock dividends	116		104		17
Net income applicable to common shareholders(1)	$	2,055	$	2,746	$	2,263
Denominator:
Weighted average common shares outstanding	401.1		431.4		464.4
Effect of dilutive potential common shares:
Stock options	4.0		4.7		4.1
Restricted stock units (non-participating) and performance stock awards	1.7		2.1		1.8
Weighted average common and dilutive potential common shares outstanding	406.8		438.2		470.3
Earnings per common share – Basic	$	5.12	$	6.37	$	4.87
Earnings per common share – Diluted	$	5.05	$	6.27	$	4.81

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⁽¹⁾  Net income applicable to common shareholders is net income less preferred stock dividends.