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Employee Incentive Plans (2007 Stock Incentive Plan, ROI Summary) (Details) - USD ($) $ in Millions | 12 Months Ended
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Dec. 31, 2018 | Dec. 31, 2017 | Dec. 31, 2016
2007 Stock Incentive Plan (Shares) |  |  |  |  |
Beginning Balance |  | 6,473,720 | 7,917,719 |  | 8,937,985
Shares Granted |  | 1,145,627 | 946,489 | [1] | 1,451,136
Shares Cancelled |  | (63,657) | (115,711) |  | (69,340)
Shares Distributed |  | (2,083,624) | (2,274,777) |  | (2,402,062)
Ending Balance |  | 5,472,066 | 6,473,720 |  | 7,917,719
Intrinsic Value Of SIP Shares Which Vested And Were Distributed [Member] |  |  |  |  |
Distributed | [2] | $ 164 | $ 81 |  | $ 88
2007 ROI Unit Stock Plan (Shares) [Member] |  |  |  |  |
Beginning Balance |  | 3,849 | 4,994 |  | 6,370
Shares Distributed |  | (3,849) | (1,145) |  | (1,376)
Ending Balance |  |  | 3,849 |  | 4,994
[1] | Stock Incentive Plan number of granted restricted stock units related to 2017 was adjusted by 23,082 additional restricted stock units during the year ended December 31, 2018.
[2] | Intrinsic value of SIP units distributed represents the compensation value reported to the participants.

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- Definition Shares granted, net of shares distributed and forfeited. + References No definition available. + Details
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- Definition Total shares distributed during the period. + References No definition available. + Details
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- Details
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- Details
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