Earnings per common share (Tables)

12 Months Ended

Dec. 31, 2017

Earnings Per Share [Abstract]

Computations of Basic Earnings Per Common Share

The computations of basic earnings per common share follow:

	Year Ended December 31
	2017			2016			2015
	(In thousands, except per share)
Income available to common shareholders:
Net income	$	1,408,306		$	1,315,114		$	1,079,667
Less: Preferred stock dividends(a)		(72,734	)		(81,270	)		(81,270	)
Net income available to common equity		1,335,572			1,233,844			998,397
Less: Income attributable to unvested stock-based    compensation awards		(8,069	)		(10,385	)		(10,708	)
Net income available to common shareholders	$	1,327,503		$	1,223,459		$	987,689
Weighted-average shares outstanding:
Common shares outstanding (including common stock    issuable) and unvested stock-based compensation awards		153,092			158,121			138,285
Less: Unvested stock-based compensation awards		(933	)		(1,341	)		(1,482	)
Weighted-average shares outstanding		152,159			156,780			136,803
Basic earnings per common share	$	8.72		$	7.80		$	7.22

(a) Including impact of not as yet declared cumulative dividends.

Computations of Diluted Earnings Per Common Share

The computations of diluted earnings per common share follow:

	Year Ended December 31
	2017			2016			2015
	(In thousands, except per share)
Net income available to common equity	$	1,335,572		$	1,233,844		$	998,397
Less: Income attributable to unvested stock-based    compensation awards		(8,055	)		(10,363	)		(10,673	)
Net income available to common shareholders	$	1,327,517		$	1,223,481		$	987,724
Adjusted weighted-average shares outstanding:
Common and unvested stock-based compensation awards		153,092			158,121			138,285
Less: Unvested stock-based compensation awards		(933	)		(1,341	)		(1,482	)
Plus: Incremental shares from assumed conversion of    stock-based compensation awards and warrants to    purchase common stock		392			524			730
Adjusted weighted-average shares outstanding		152,551			157,304			137,533
Diluted earnings per common share	$	8.70		$	7.78		$	7.18