Goodwill, Customer Relationships and Other Intangible Assets (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended		6 Months Ended		6 Months Ended		3 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Dec. 31, 2011	Jun. 30, 2012 Customer relationships Y	Dec. 31, 2011 Customer relationships	Jun. 30, 2012 Capitalized software Y	Dec. 31, 2011 Capitalized software	Mar. 31, 2011 Predecessor
Goodwill, Customer Relationships and Other Intangible Assets
Goodwill	$ 9,369		$ 9,369	$ 9,369
Customer relationships and other intangible assets subject to amortization
Customer relationships, less accumulated amortization	4,742		4,742	5,101	4,742	5,101
Capitalized software, less accumulated amortization	1,329		1,329	1,460			1,329	1,460
Accumulated amortization					957	598	556	354
Other intangible assets subject to amortization
Estimated life (in years)					10
Estimated life, maximum (in years)							7
Amortization expense	$ 287	$ 319	$ 561						$ 58