Consolidated Statements of Changes in Stockholders' Equity (Deficit) - USD ($) $ in Millions | Total | Common Stock | Additional Paid-in Capital | Accumulated Deficit | Accumulated Other Comprehensive Loss | Previously Reported [Member] | Previously Reported [Member]Accumulated Deficit |
Beginning Balance (in shares) at Sep. 30, 2018 | | 110,200,000 | | | | | |
Beginning Balance at Sep. 30, 2018 | $ 2,051 | $ 1 | $ 1,745 | $ 287 | $ 18 | | |
Increase (Decrease) in Stockholders' Equity [Roll Forward] | | | | | | | |
Issuance of common stock, net of shares redeemed and canceled, under employee stock option plan (in shares) | | 800,000 | | | | | |
Issuance of common stock, net of shares redeemed and canceled, under employee stock option plan | 0 | | | | | | |
Stock Repurchased During Period, Shares | | (300,000) | | | | | |
Amortization of share-based compensation | 6 | | 6 | | | | |
Net income (loss) | 9 | | | | | | |
Other comprehensive income (loss) | (20) | | | | (20) | | |
Shares repurchased and retired for tax withholding on vesting of restricted stock units | (6) | | (6) | | | | |
Ending Balance at Dec. 31, 2018 | 2,132 | $ 1 | 1,745 | 388 | (2) | | |
Ending Balance (in shares) at Dec. 31, 2018 | | 110,700,000 | | | | | |
Beginning Balance (in shares) at Sep. 30, 2018 | | 110,200,000 | | | | | |
Beginning Balance at Sep. 30, 2018 | 2,051 | $ 1 | 1,745 | 287 | 18 | | |
Increase (Decrease) in Stockholders' Equity [Roll Forward] | | | | | | | |
Net income (loss) | (637) | | | | | | |
Other comprehensive income (loss) | (50) | | | | | | |
Ending Balance at Jun. 30, 2019 | 1,470 | $ 1 | 1,756 | (255) | (32) | | |
Ending Balance (in shares) at Jun. 30, 2019 | | 110,900,000 | | | | | |
Beginning Balance (in shares) at Dec. 31, 2018 | | 110,700,000 | | | | | |
Beginning Balance at Dec. 31, 2018 | 2,132 | $ 1 | 1,745 | 388 | (2) | | |
Increase (Decrease) in Stockholders' Equity [Roll Forward] | | | | | | | |
Amortization of share-based compensation | 5 | | 5 | | | | |
Net income (loss) | (13) | | | | | | |
Other comprehensive income (loss) | 8 | | | | 8 | | |
Ending Balance at Mar. 31, 2019 | 2,135 | $ 1 | 1,750 | 378 | 6 | | |
Ending Balance (in shares) at Mar. 31, 2019 | | 110,700,000 | | | | | |
Increase (Decrease) in Stockholders' Equity [Roll Forward] | | | | | | | |
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets | Accounting Standards Update 2014-09 [Member] | | | | | | $ 3 | $ 3 |
Issuance of common stock, net of shares redeemed and canceled, under employee stock option plan (in shares) | | 300,000 | | | | | |
Issuance of common stock, net of shares redeemed and canceled, under employee stock option plan | 0 | | | | | | |
Stock Repurchased During Period, Shares | | (100,000) | | | | | |
Amortization of share-based compensation | 8 | | 8 | | | | |
Net income (loss) | (633) | | | | | | |
Other comprehensive income (loss) | (38) | | | | (38) | | |
Shares repurchased and retired for tax withholding on vesting of restricted stock units | (2) | | (2) | | | | |
Ending Balance at Jun. 30, 2019 | 1,470 | $ 1 | 1,756 | (255) | (32) | | |
Ending Balance (in shares) at Jun. 30, 2019 | | 110,900,000 | | | | | |
Beginning Balance (in shares) at Sep. 30, 2019 | | 111,000,000 | | | | | |
Beginning Balance at Sep. 30, 2019 | 1,300 | $ 1 | $ 1,761 | (289) | (173) | | |
Increase (Decrease) in Stockholders' Equity [Roll Forward] | | | | | | | |
Issuance of common stock, net of shares redeemed and canceled, under employee stock option plan (in shares) | | 300,000 | | | | | |
Issuance of common stock, net of shares redeemed and canceled, under employee stock option plan | $ 0 | | | | | | |
Share-based Payment Arrangement, Shares Withheld for Tax Withholding Obligation | | 100,000 | | | | | |
Stock Repurchased and Retired During Period, Shares | (142,000,000) | (10,700,000) | (142,000,000) | | | | |
Amortization of share-based compensation | $ 6 | | $ 6 | | | | |
Preferred Stock, Accretion of Redemption Discount | (4) | | (4) | | | | |
Accrued dividends on Series A preferred stock | (1) | | (1) | | | | |
Net income (loss) | (54) | | | | | | |
Other comprehensive income (loss) | 10 | | | | 10 | | |
Shares repurchased and retired for tax withholding on vesting of restricted stock units | (2) | | (2) | | | | |
Ending Balance at Dec. 31, 2019 | 1,113 | $ 1 | 1,618 | (343) | (163) | | |
Ending Balance (in shares) at Dec. 31, 2019 | | 100,500,000 | | | | | |
Beginning Balance (in shares) at Sep. 30, 2019 | | 111,000,000 | | | | | |
Beginning Balance at Sep. 30, 2019 | $ 1,300 | $ 1 | 1,761 | (289) | (173) | | |
Increase (Decrease) in Stockholders' Equity [Roll Forward] | | | | | | | |
Stock Repurchased During Period, Shares | (28,923,664) | | | | | | |
Accrued dividends on Series A preferred stock | $ (3) | | | | | | |
Net income (loss) | (717) | | | | | | |
Other comprehensive income (loss) | (52) | | | | | | |
Ending Balance at Jun. 30, 2020 | 211 | $ 1 | 1,441 | (1,006) | (225) | | |
Ending Balance (in shares) at Jun. 30, 2020 | | 82,900,000 | | | | | |
Beginning Balance (in shares) at Dec. 31, 2019 | | 100,500,000 | | | | | |
Beginning Balance at Dec. 31, 2019 | 1,113 | $ 1 | $ 1,618 | (343) | (163) | | |
Increase (Decrease) in Stockholders' Equity [Roll Forward] | | | | | | | |
Issuance of common stock, net of shares redeemed and canceled, under employee stock option plan (in shares) | | 600,000 | | | | | |
Issuance of common stock, net of shares redeemed and canceled, under employee stock option plan | $ 0 | | | | | | |
Share-based Payment Arrangement, Shares Withheld for Tax Withholding Obligation | | 200,000 | | | | | |
Stock Repurchased and Retired During Period, Shares | (188,000,000) | (18,200,000) | (188,000,000) | | | | |
Amortization of share-based compensation | $ 8 | | $ 8 | | | | |
Accrued dividends on Series A preferred stock | (1) | | (1) | | | | |
Net income (loss) | (672) | | | | | | |
Other comprehensive income (loss) | (55) | | | | (55) | | |
Shares repurchased and retired for tax withholding on vesting of restricted stock units | (1) | | (1) | | | | |
Ending Balance at Mar. 31, 2020 | 204 | $ 1 | 1,436 | (1,015) | (218) | | |
Ending Balance (in shares) at Mar. 31, 2020 | | 82,700,000 | | | | | |
Increase (Decrease) in Stockholders' Equity [Roll Forward] | | | | | | | |
Issuance of common stock, net of shares redeemed and canceled, under employee stock option plan (in shares) | | 300,000 | | | | | |
Issuance of common stock, net of shares redeemed and canceled, under employee stock option plan | 0 | | | | | | |
Share-based Payment Arrangement, Shares Withheld for Tax Withholding Obligation | | 100,000 | | | | | |
Amortization of share-based compensation | 7 | | 7 | | | | |
Accrued dividends on Series A preferred stock | (1) | | (1) | | | | |
Net income (loss) | 9 | | | | | | |
Other comprehensive income (loss) | (7) | | | | | | |
Shares repurchased and retired for tax withholding on vesting of restricted stock units | (1) | | (1) | | | | |
Ending Balance at Jun. 30, 2020 | $ 211 | $ 1 | $ 1,441 | $ (1,006) | $ (225) | | |
Ending Balance (in shares) at Jun. 30, 2020 | | 82,900,000 | | | | | |