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Earnings Per Share - Narrative (Details) - USD ($) shares in Thousands, $ in Millions | 3 Months Ended | 6 Months Ended |  |  |  |  |
--- | --- | --- | --- | --- | --- | --- | ---
Jun. 30, 2019 | Jul. 31, 2018 | Jun. 30, 2018 | Jun. 30, 2019 | Jun. 30, 2018 | Jan. 16, 2019 | Apr. 20, 2018 | Mar. 31, 2018 | Feb. 28, 2018 | Oct. 31, 2017
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] |  |  |  |  |  |  |  |  |  |
Shares repurchased (in shares) | 11,000 |  | 16,000 | 23,000 | 31,000 |  |  |  |  |
2018 |  |  |  |  |  |  |  |  |  |
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] |  |  |  |  |  |  |  |  |  |
Accelerated share repurchase program (payment) receipt amount |  |  |  |  |  |  | $ 450 |  |  |
Initial share value received |  | $ 90 |  |  |  |  | $ 360 | $ 150 |  |
Initial shares received (in shares) |  |  |  |  |  |  | 6,000 | 3,000 |  |
Shares repurchased (in shares) |  | 7,000 |  |  |  |  |  |  |  |
Share Repurchase Program October 2017 |  |  |  |  |  |  |  |  |  |
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] |  |  |  |  |  |  |  |  |  |
Share repurchase program authorized amount |  |  |  |  |  |  |  |  |  | $ 1,500
Share Repurchase Program February 2018 |  |  |  |  |  |  |  |  |  |
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] |  |  |  |  |  |  |  |  |  |
Share repurchase program authorized amount |  |  |  |  |  |  |  |  | $ 5,000 |
Share Repurchase Program January 2019 |  |  |  |  |  |  |  |  |  |
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] |  |  |  |  |  |  |  |  |  |
Share repurchase program authorized amount |  |  |  |  |  | $ 5,000 |  |  |  |
Stock Options |  |  |  |  |  |  |  |  |  |
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items] |  |  |  |  |  |  |  |  |  |
Antidilutive securities excluded from diluted earnings per share calculation | 900 |  | 1,000 | 800 | 900 |  |  |  |  |

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- Definition Amount of cash receipt from (payment to) bank; or stock received from (issuance to) bank in the settlement of the accelerated share repurchase agreement. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 30 -Section 25 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=6405686&loc=d3e22802-112653 + Details
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- Definition Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 260 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=6371337&loc=d3e3550-109257 + Details
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