Stockholders' Equity (Details) - $ / shares	1 Months Ended	12 Months Ended
Jun. 30, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Stock
Repurchases of common stock (shares)		(18,595,315)
Preferred stock, dividend rate	4.00%	4.00%	4.00%
Dividend rate (USD per share)	$ 2.12
Shares reserved for issuance under stock plans, dividend reinvestment program and conversion of Preferred and Preference Stock		37,116,835
Common Stock
Stock
Shares outstanding (shares)		187,675,082	186,603,738	185,668,718
Issuance of common stock (shares)		1,276,797	1,043,809	881,480
Conversions to common stock (shares)		92,379	27,535	53,540
Shares outstanding (shares)		170,448,943	187,675,082	186,603,738
Treasury Stock
Stock
Shares outstanding (shares)		135,662,830	136,734,174	137,669,194
Issuance of common stock (shares)		1,276,797	1,043,809	881,480
Conversions to common stock (shares)		92,379	27,535	53,540
Shares outstanding (shares)		152,888,969	135,662,830	136,734,174

Aggregate number of common shares reserved for future issuance.

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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The amount per share used to calculated dividend payments on preferred stock.

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The percentage rate used to calculate dividend payments on preferred stock.

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Number of shares issued which are neither cancelled nor held in the treasury.

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Number of shares issued during the period as a result of the conversion of convertible securities.

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Number of treasury shares or units reissued. Excludes reissuance of shares or units in treasury for award under share-based payment arrangement.

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Number of shares that have been repurchased during the period and are being held in treasury.

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