Equity (Tables)

12 Months Ended

Dec. 31, 2015

Equity [Abstract]

Schedule of Stockholders Equity [Table Text Block]

The following table presents changes in the number of shares issued and outstanding.

Year ended December 31, (in shares)	2015		2014		2013
Common stock
Total issued, January 1,	480,136,039		479,767,470		412,600,700
New issuances
Employee benefits and compensation plans	2,654,657		368,569		—
Private placement (a)	—		—		67,166,770
Total issued, December 31,	482,790,696		480,136,039		479,767,470
Total treasury stock, December 31,	(810,585	)	(41,148	)	—
Total outstanding, December 31,	481,980,111		480,094,891		479,767,470

(a) On November 20, 2013, Ally completed its private placement of its common stock for an aggregate price of $1.3 billion.

Schedule of Stock by Class [Table Text Block]

The following table summarizes information about our Series A and Series G preferred stock.

	December 31, 2015			December 31, 2014
Series A preferred stock (a)
Carrying value ($ in millions)	$	696		$	1,021
Par value (per share)	0.01			0.01
Liquidation preference (per share)	25			25
Number of shares authorized	40,870,560			40,870,560
Number of shares issued and outstanding	27,870,560			40,870,560
Dividend/coupon
Prior to May 15, 2016	8.5		%	8.5		%
On and after May 15, 2016	Three month LIBOR + 6.243%			Three month LIBOR + 6.243%
Series G preferred stock
Carrying value ($ in millions)	$	—		$	234
Par value (per share)	—			0.01
Liquidation preference (per share)	—			1,000
Number of shares authorized	—			2,576,601
Number of shares issued and outstanding	—			2,576,601
Dividend/coupon	—		%	7		%

(a) Nonredeemable prior to May 15, 2016.