Employee Benefits (Defined Benefit Plans Disclosures) (Details) (USD $) In Millions	3 Months Ended	6 Months Ended	3 Months Ended	6 Months Ended	3 Months Ended		9 Months Ended	3 Months Ended		9 Months Ended
	Sep. 30, 2011 Pension Plan [Member] Successor [Member]	Sep. 30, 2011 Pension Plan [Member] Successor [Member]	Sep. 30, 2011 Post-retirement Benefit Plans [Member] Successor [Member]	Sep. 30, 2011 Post-retirement Benefit Plans [Member] Successor [Member]	Mar. 31, 2011 Pension Plan [Member] Predecessor [Member]	Sep. 30, 2010 Pension Plan [Member] Predecessor [Member]	Sep. 30, 2010 Pension Plan [Member] Predecessor [Member]	Mar. 31, 2011 Post-retirement Benefit Plans [Member] Predecessor [Member]	Sep. 30, 2010 Post-retirement Benefit Plans [Member] Predecessor [Member]	Sep. 30, 2010 Post-retirement Benefit Plans [Member] Predecessor [Member]
Net periodic benefits expense:
Service cost	$ 14	$ 27	$ 2	$ 3	$ 14	$ 13	$ 40	$ 2	$ 1	$ 5
Interest cost	106	214	42	83	104	112	336	41	46	137
Expected return on plan assets	(139)	(278)	(13)	(25)	(133)	(139)	(417)	(13)	(15)	(45)
Amortization of unrecognized prior service costs					(6)	(5)	(16)	(24)	(25)	(75)
Amortization of unrecognized net actuarial loss					31	33	98	10	10	30
Net periodic benefit (income) expense	$ (19)	$ (37)	$ 31	$ 61	$ 10	$ 14	$ 41	$ 16	$ 17	$ 52