Stock-Based Compensation (Notes)	12 Months Ended
Stock-Based Compensation (Notes)	Dec. 31, 2020
Share-based Payment Arrangement [Abstract]
Stock-Based Compensation	STOCK-BASED COMPENSATION The Company grants stock-based compensation awards to certain senior management members, employees and directors including non-qualified stock options, restricted stock units ("RSUs") and performance share units ("PSUs"). The Company's stockholders approved the 2018 Long-Term Incentive Plan (the "2018 Plan") at the 2018 Annual Meeting of Stockholders held on May 2, 2018. Upon approval of the 2018 Plan, the 2012 Amended and Restated Long-Term Incentive Plan, as amended (the "2012 Plan") was terminated, no future awards were permitted to be granted under the 2012 Plan, and any shares available for future issuance under the 2012 Plan were canceled. Under the 2018 Plan, 6 million shares were authorized for issuance plus any shares that expire or are forfeited under the 2012 Plan after March 1, 2018. As of December 31, 2020, there are approximately 2 million shares available for future grants. The form of equity award agreements under the 2012 and 2018 Plans include a retirement provision for equity grants which provide for continued vesting of awards once an employee has attained the age of 65 years, or 55 years of age or older plus at least ten years of tenure with the Company, provided they have been employed or provided services to the Company for one year following the date of grant or start of the performance period. Historically, equity awards granted annually generally included a mix of RSUs, PSUs and options. However in 2020, the Company shifted away from granting options, limited equity awards to a small group of executives and granted other key employees cash-based awards, including cash-based RSUs. RSUs granted vest over three years, with 33.33% vesting on each anniversary of the grant date. The fair value of RSUs is equal to the closing sale price of the Company's common stock on the date of grant. During 2020, the Company granted restricted stock unit awards related to 0.8 million shares with a weighted average grant date fair value of $8.70 which includes shares granted to certain executives in February 2020 and directors in May 2020. There were 2.7 million shares underlying share-settled RSUs outstanding at December 31, 2020 with a weighted average grant date fair value of $14.42. PSUs are incentives that reward grantees based upon the Company's financial performance over a three-year performance period which begins January 1st of the grant year and ends on December 31st of the third year following the grant year. These awards are measured according to two metrics: one is based upon the total stockholder return of Realogy's common stock relative to the total stockholder return of the SPDR S&P Homebuilders Index ("XHB") or the S&P MidCap 400 index (the "RTSR award"), and the other is based upon the achievement of cumulative free cash flow goals. The payout under each PSU award is variable and based upon the extent to which the performance goals are achieved over the performance period (with a range of payout from 0% to 175% of target for the RTSR award and 0% to 200% of target for the achievement of cumulative free cash flow award) and will be distributed during the first quarter after the end of the performance period. The fair value of PSU awards without a market condition is equal to the closing sale price of the Company's common stock on the date of grant and the fair value of the RTSR awards is estimated on the date of grant using the Monte Carlo Simulation method. In February 2020, the Company granted performance stock unit awards related to 0.9 million shares with a weighted average grant date fair value of $9.23 to certain executives. There were 2.3 million shares outstanding at December 31, 2020 with a weighted average grant date fair value of $14.01. Stock options have a maximum term of ten years and vest over four years, with 25% vesting on each anniversary date of the grant date. The options have an exercise price equal to the closing sale price of the Company's common stock on the date of grant. The fair value of the options is estimated on the date of grant using the Black-Scholes option-pricing model. There were 3.8 million options outstanding at December 31, 2020 with a weighted average exercise price of $26.19, including 2.9 million exercisable, which have an intrinsic value of zero and a weighted average remaining contractual life of 3.5 years. Stock-Based Compensation Expense As of December 31, 2020, based on current performance achievement expectations, there was $24 million of unrecognized compensation cost related to incentive equity awards under the plans which would be recorded in future periods as compensation expense over a remaining weighted average period of approximately 1.5 years. The Company recorded stock-based compensation expense related to the incentive equity awards of $39 million, $30 million and $40 million for the years ended December 31, 2020, 2019 and 2018, respectively.