Income Taxes	9 Months Ended
Sep. 30, 2018
Income Tax Disclosure [Abstract]
Income Tax Disclosure [Text Block]	NOTE 12 - INCOME TAXES For the three months ended September 30, 2018 and 2017, the provision for income taxes was $95 million and $225 million, representing effective tax rates of 11% and 29%, respectively. For the nine months ended September 30, 2018 and 2017, the provision for income taxes was $412 million and $606 million, representing effective tax rates of 16% and 28%, respectively. The effective tax rate for the nine months ended September 30, 2018 was favorably impacted by a net $71 million discrete income tax benefit, while the effective tax rate for the nine months ended September 30, 2017 was favorably impacted by a net $26 million discrete income tax benefit related primarily to share-based compensation. The $71 million net discrete income tax benefit for the nine months ended September 30, 2018 was driven by a $55 million tax benefit for the income tax effects of the 2017 Tax Act, a $22 million tax benefit for share-based compensation, and an $8 million tax benefit related to the release of certain UTBs due to the expiration of the applicable statute of limitation. These income tax benefits were offset partially by a $14 million discrete tax expense resulting from the merger of the Company's STM and Bank legal entities, which includes the $35 million discrete tax expense in the first quarter of 2018 related to the increase in the valuation allowance recorded for STM's state carryforwards and a $21 million discrete tax benefit in the third quarter of 2018 related to the net adjustment of STM’s state DTAs and DTLs upon completion of the merger. The $55 million adjustment for the income tax effects of the 2017 Tax Act reflects the final adjustment to the Company's December 31, 2017 DTAs and DTLs at the reduced federal corporate income tax rate of 21%. This adjustment completed the Company's accounting for the income tax effects of the 2017 Tax Act. At September 30, 2018 and December 31, 2017, the Company had a valuation allowance against its state carryforwards and certain state DTAs of $89 million and $143 million, respectively. This decrease in the valuation allowance was due primarily to the reversal of the valuation allowance that was recorded against certain of STM's pre-merger state NOL carryforwards that could not be carried forward by the Bank after the merger. The reversal of the valuation allowance was offset by the write-off of the related state NOL carryforwards. See Note 18, “Business Segment Reporting,” for additional information regarding the merger of STM and the Bank. The provision for income taxes includes both federal and state income taxes and differs from the provision using statutory rates due primarily to favorable permanent tax items such as interest income from lending to tax-exempt entities, tax credits, and amortization expense related to qualified affordable housing investment costs. The Company calculated the provision for income taxes by applying the estimated annual effective tax rate to year-to-date pre-tax income and adjusting for discrete items that occurred during the period

NOTE 12 - INCOME TAXES

For the three months ended September 30, 2018 and 2017, the provision for income taxes was $95 million and $225 million, representing effective tax rates of 11% and 29%, respectively. For the nine months ended September 30, 2018 and 2017, the provision for income taxes was $412 million and $606 million, representing effective tax rates of 16% and 28%, respectively. The effective tax rate for the nine months ended September 30, 2018 was favorably impacted by a net $71 million discrete income tax benefit, while the effective tax rate for the nine months ended September 30, 2017 was favorably impacted by a net $26 million discrete income tax benefit related primarily to share-based compensation.

The $71 million net discrete income tax benefit for the nine months ended September 30, 2018 was driven by a $55 million tax benefit for the income tax effects of the 2017 Tax Act, a $22 million tax benefit for share-based compensation, and an $8 million tax benefit related to the release of certain UTBs due to the expiration of the applicable statute of limitation. These income tax benefits were offset partially by a $14 million discrete tax expense resulting from the merger of the Company's STM and Bank legal entities, which includes the $35 million discrete tax expense in the first quarter of 2018 related to the increase in the valuation allowance recorded for STM's state carryforwards and a $21 million discrete tax benefit in the third quarter of 2018 related to the net adjustment of STM’s state DTAs and DTLs upon completion of the merger. The $55 million adjustment for the income tax effects of the 2017 Tax Act reflects the final adjustment to the Company's December 31, 2017 DTAs and DTLs at the reduced federal corporate income tax rate of 21%. This adjustment completed the Company's accounting for the income tax effects of the 2017 Tax Act.

At September 30, 2018 and December 31, 2017, the Company had a valuation allowance against its state carryforwards and certain state DTAs of $89 million and $143 million, respectively. This decrease in the valuation allowance was due primarily to the reversal of the valuation allowance that was recorded against certain of STM's pre-merger state NOL carryforwards that could not be carried forward by the Bank after the merger. The reversal of the valuation allowance was offset by the write-off of the related state NOL carryforwards. See Note 18, “Business Segment Reporting,” for additional information regarding the merger of STM and the Bank.

The provision for income taxes includes both federal and state income taxes and differs from the provision using statutory rates due primarily to favorable permanent tax items such as interest income from lending to tax-exempt entities, tax credits, and amortization expense related to qualified affordable housing investment costs. The Company calculated the provision for income taxes by applying the estimated annual effective tax rate to year-to-date pre-tax income and adjusting for discrete items that occurred during the period