Stockholders' Equity	6 Months Ended
Jun. 30, 2018
Equity [Abstract]
Stockholders' Equity	Stockholders’ Equity Preferred Stock. The Corporation is authorized to issue 10 million shares of preferred stock without par value. The Board of Directors is authorized to fix the particular designations, preferences and relative, participating, optional and other special rights and qualifications, limitations or restrictions for each series of preferred stock issued. As of June 30, 2018, the Corporation had issued and outstanding 500,000 depositary shares, each representing a 1/100th ownership interest in a share of Series D Non-Cumulative Perpetual Preferred Stock (the “Series D Preferred Stock”) issued in August 2016. Equity related to Series D Preferred Stock as of June 30, 2018 and December 31, 2017 was $493.5 million. Shares of the Series D Preferred Stock have no par value and a liquidation preference of $100,000 (equivalent to $1,000 per depositary share). Dividends on the Series D Preferred Stock, which are not mandatory, accrue and are payable on the liquidation preference amount, on a non-cumulative basis, at a rate per annum equal to (i) 4.60% from the original issue date of the Series D Preferred Stock to but excluding October 1, 2026; and (ii) a floating rate equal to Three-Month LIBOR plus 3.202% from and including October 1, 2026. Fixed rate dividends are payable in arrears on the 1st day of April and October of each year, through and including October 1, 2026, and floating rate dividends will be payable in arrears on the 1st day of January, April, July and October of each year, commencing on January 1, 2027. As of June 30, 2018, the Corporation also had issued and outstanding 16 million depositary shares, each representing 1/1000th ownership interest in a share of Series C Non-Cumulative Perpetual Preferred Stock (“Series C Preferred Stock”), issued in August 2014. Equity related to Series C Preferred Stock as of June 30, 2018 and December 31, 2017 was $388.5 million. Series C Preferred Stock has no par value and has a liquidation preference of $25,000 (equivalent to $25 per depositary share). Dividends on the Series C Preferred Stock, which are not mandatory, accrue and are payable on the liquidation preference amount, on a non-cumulative basis, quarterly in arrears on the first day of January, April, July and October of each year, at a rate per annum equal to 5.85%. On April 17, 2018, the Corporation declared a cash dividend of $365.625 per share of Series C Preferred Stock payable on July 1, 2018, to stockholders of record as of June 15, 2018. Common Stock. During the three and six months ended June 30, 2018, the Corporation repurchased 1,787,701 shares of common stock, including 5,986 shares withheld related to share-based compensation, at a total cost of $190.6 million ($106.63 average price per share) and 4,305,710 shares of common stock, including 385,109 shares withheld related to share-based compensation, at a total cost of $453.8 million ($105.39 average price per share), respectively. These repurchases were made under the common stock repurchase authorization approved by the Corporation’s Board of Directors in July 2017. On July 17, 2018, this program was terminated and replaced with a new repurchase program, under which the Corporation’s Board of Directors authorized the Corporation to repurchase up to 25.0 million shares of the Corporation’s common stock. Shares repurchased by the Corporation are used for general purposes, including management of the Corporation’s capital level and the issuance of shares under stock option and other incentive plans of the Corporation. The repurchase authorization approved by the Board of Directors has no expiration date. Under the Corporation’s 2018 Capital Plan, which was reviewed without objection by the Federal Reserve, the Corporation may repurchase up to $1.0 billion of common stock after June 30, 2018 through June 30, 2019.

Stockholders’ Equity

Preferred Stock. The Corporation is authorized to issue 10 million shares of preferred stock without par value. The Board of Directors is authorized to fix the particular designations, preferences and relative, participating, optional and other special rights and qualifications, limitations or restrictions for each series of preferred stock issued.

As of June 30, 2018, the Corporation had issued and outstanding 500,000 depositary shares, each representing a 1/100th ownership interest in a share of Series D Non-Cumulative Perpetual Preferred Stock (the “Series D Preferred Stock”) issued in August 2016. Equity related to Series D Preferred Stock as of June 30, 2018 and December 31, 2017 was $493.5 million. Shares of the Series D Preferred Stock have no par value and a liquidation preference of $100,000 (equivalent to $1,000 per depositary share).

Dividends on the Series D Preferred Stock, which are not mandatory, accrue and are payable on the liquidation preference amount, on a non-cumulative basis, at a rate per annum equal to (i) 4.60% from the original issue date of the Series D Preferred Stock to but excluding October 1, 2026; and (ii) a floating rate equal to Three-Month LIBOR plus 3.202% from and including October 1, 2026. Fixed rate dividends are payable in arrears on the 1st day of April and October of each year, through and including October 1, 2026, and floating rate dividends will be payable in arrears on the 1st day of January, April, July and October of each year, commencing on January 1, 2027.

As of June 30, 2018, the Corporation also had issued and outstanding 16 million depositary shares, each representing 1/1000th ownership interest in a share of Series C Non-Cumulative Perpetual Preferred Stock (“Series C Preferred Stock”), issued in August 2014. Equity related to Series C Preferred Stock as of June 30, 2018 and December 31, 2017 was $388.5 million. Series C Preferred Stock has no par value and has a liquidation preference of $25,000 (equivalent to $25 per depositary share).

Dividends on the Series C Preferred Stock, which are not mandatory, accrue and are payable on the liquidation preference amount, on a non-cumulative basis, quarterly in arrears on the first day of January, April, July and October of each year, at a rate per annum equal to 5.85%. On April 17, 2018, the Corporation declared a cash dividend of $365.625 per share of Series C Preferred Stock payable on July 1, 2018, to stockholders of record as of June 15, 2018.

Common Stock. During the three and six months ended June 30, 2018, the Corporation repurchased 1,787,701 shares of common stock, including 5,986 shares withheld related to share-based compensation, at a total cost of $190.6 million ($106.63 average price per share) and 4,305,710 shares of common stock, including 385,109 shares withheld related to share-based compensation, at a total cost of $453.8 million ($105.39 average price per share), respectively. These repurchases were made under the common stock repurchase authorization approved by the Corporation’s Board of Directors in July 2017. On July 17, 2018, this program was terminated and replaced with a new repurchase program, under which the Corporation’s Board of Directors authorized the Corporation to repurchase up to 25.0 million shares of the Corporation’s common stock. Shares repurchased by the Corporation are used for general purposes, including management of the Corporation’s capital level and the issuance of shares under stock option and other incentive plans of the Corporation. The repurchase authorization approved by the Board of Directors has no expiration date.

Under the Corporation’s 2018 Capital Plan, which was reviewed without objection by the Federal Reserve, the Corporation may repurchase up to $1.0 billion of common stock after June 30, 2018 through June 30, 2019.