Stock-Based Compensation (Narrative)(Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance shares awarded in 2013, outstanding and contingent on meeting performance objectives through 2016 and provision of service by the employees	4,944,575
Percent level objectives were met through the current year for performance shares awarded primarily in 2013	86.00%
Performance shares at the current fiscal year's performance level	4,252,335
Shares to be distributed early next fiscal year from the 2013 performance shares	2,552,949
Shares to be distributed to employees providing one additional year of service from the 2013 performance shares	1,699,386
Performance shares distributed from 2010 performance share awards, rights to receive	4,823,045
Performance shares distributed from 2010 performance share awards, shares issued	2,782,143
Performance shares distributed from 2010 performance share awards, withheld for income taxes	1,829,617
Performance shares distributed from 2010 performance share awards, paid in cash	211,285
Performance shares canceled from 2010 Performance Share Awards	14,694
Total compensation expense for stock option and incentive shares plans	$ 145	$ 24	$ 123
Income tax benefits recognized in income statement for compensation arrangements	45	$ 2	$ 39
Unrecognized compensation cost related to non-vested awards granted	$ 133
Unrecognized compensation cost is expected to be recognized, weighted-average period, years	1 year 10 months
Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Performance shares awarded in 2013, outstanding and contingent on meeting performance objectives through 2016 and provision of service by the employees	2,186,150
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Percentage of options granted at the closing market price of common stock on the grant date	100.00%
Amount of stock option vesting per year	one-third
Stock option expiration years from date of grant years	10 years
Share-based compensation arrangement by share-based payment award, number of shares available for grant	10,900,000
Weighted-average price of shares granted	$ 9.02	$ 12.48	$ 14.83
Cash received for stock options exercises	$ 31	$ 36	$ 77
Options exercised, total intrinsic value	9	16	61
Actual tax benefit realized from tax deductions related to option exercises	$ 2	$ 10	$ 14
Risk-free interest rate	1.90%	1.90%	2.00%
Expected dividend yield	3.80%	3.10%	2.60%
Expected volatility rate	27.00%	28.00%	28.00%
Expected life of option	7 years	7 years	7 years
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares vested in period	235,000
Common shares issued	139,436
Shares withheld for income tax	95,564
Unvested shares outstanding	1,174,500
Incentive Shares Member
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, number of shares available for grant	15,400,000
Shares vested in period	235,000
Unvested shares outstanding	7,328,000	6,377,000
Total fair value of shares vested	$ 11	$ 9	$ 315
Cash paid primarily for tax withholdings	$ 4	5	134
Restricted Stock For Non Management Directors Member
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award, number of shares available for grant	194,577
Restricted stock awarded	24,336
Restricted stock units awarded	3,042
Includes both Continuing and Discontinued Operations [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total compensation expense for stock option and incentive shares plans	$ 159	30	143
Discontinued Operations, Held-for-sale [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total compensation expense for stock option and incentive shares plans	$ 14	$ 6	$ 20