Employee Benefit Plans (Retirement Plan Expense) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	6 Months Ended		12 Months Ended
	Dec. 31, 2014	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2014	Dec. 31, 2013	Jun. 30, 2012
Defined Benefit Plan Disclosure [Line Items]
Settlement charges	$ 98
Defined contribution plans		23	23	50	44	45
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost (benefits earned during the period)		44	36	71	84	71
Interest cost		61	65	126	114	130
Expected return on plan assets		(75)	(70)	(155)	(144)	(141)
Settlement charges		68	0	95	0
Remeasurement charge						30
Amortization of actuarial loss		42	24	36	74	52
Defined Benefit Plan, Other Costs		2	2	3	3	5
Net periodic defined benefit plan expense		142	57	176	131	147
Pension Expense		165	80	226	175	192
Other Postretirement Benefit Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost (benefits earned during the period)		4	3	4	5	7
Interest cost		6	6	8	7	12
Remeasurement charge						4
Amortization of actuarial loss				2	5
Defined Benefit Plan, Other Costs				(18)	(18)	(2)
Net periodic defined benefit plan expense		10	9	(4)	(1)	21
Pension Expense		$ 10	$ 9	$ (4)	$ (1)	$ 21